Philo (God speaking to Moses): "Do not, then, ever expect to be able to comprehend me nor any one of my powers, in respect of our essence"

"(41) Which that interpreter of the divine word, Moses, the man most beloved by God, having a regard to, besought God and said, "Show me thyself"--all but urging him, and crying out in loud and distinct words--"that thou hast a real being and existence the whole world is my teacher, assuring me of the fact and instructing me as a son might of the existence of his father, or the work of the existence of the workman. But, though I am very desirous to know what thou art as to thy essence, I can find no one who is able to explain to me anything relating to this branch of learning in any part of the universe whatever. (42) On which account, I beg and entreat of thee to receive the supplication of a man who is thy suppliant and devoted to God's service, and desirous to serve thee alone; for as the light is not known by the agency of anything else, but is itself its own manifestation, so also thou must alone be able to manifest thyself. For which reason I hope to receive pardon, if, from want of any one to teach me, I am so bold as to flee to thee, desiring to receive instruction from thyself." (43) But God replied, "I receive, indeed, your eagerness, inasmuch as it is praiseworthy; but the request which you make is not fitting to be granted to any created being. And I only bestow such gifts as are appropriate to him who receives them; for it is not possible for a man to receive all that it is easy for me to give. On which account I give to him who is deserving of my favour all the gifts which he is able to receive. (44) But not only is the nature of mankind, but even the whole heaven and the whole world is unable to attain to an adequate comprehension of me. So know yourself, and be not carried away with impulses and desires beyond your power; and let not a desire of unattainable objects carry you away and keep you in suspense. For you shall not lack anything which may be possessed by you." (45) When Moses heard this he betook himself to a second supplication, and said, "I am persuaded by thy explanations that I should not have been able to receive the visible appearance of thy form. But I beseech thee that I may, at all events, behold the glory that is around thee. And I look upon thy glory to be the powers which attend thee as thy guards, the comprehension of which having escaped me up to the present time, worketh in me no slight desire of a thorough understanding of it." (46) But God replied and said, "The powers which you seek to behold are altogether invisible, and appreciable only by the intellect; since I myself am invisible and only appreciable by the intellect. And what I call appreciable only by the intellect are not those which are already comprehended by the mind, but those which, even if they could be so comprehended, are still such that the outward senses could not at all attain to them, but only the very purest intellect. (47) And though they are by nature incomprehensible in their essence, still they show a kind of impression or copy of their energy and operation; as seals among you, when any wax or similar kind of material is applied to them, make an innumerable quantity of figures and impressions, without being impaired as to any portion of themselves, but still remaining unaltered and as they were before; so also you must conceive that the powers which are around me invest those things which have no distinctive qualities with such qualities, and those which have no forms with precise forms, and that without having any portion of their own everlasting nature dismembered or weakened. (48) And some of your race, speaking with sufficient correctness, call them ideas (ideai), since they give a peculiar character (idiopoiousi) to every existing thing, arranging what had previously no order, and limiting, and defining, and fashioning what was before destitute of all limitation, and defination, and fashion; and, in short, in all respects changing what was bad into a better condition. (49) "Do not, then, ever expect to be able to comprehend me nor any one of my powers, in respect of our essence. But, as I have said, I willingly and cheerfully grant unto you such things as you may receive. And this gift is to call you to the beholding of the world and all the things that are in it, which must be comprehended, not indeed by the eyes of the body, but by the sleepless vision of the soul. (50) The desire of wisdom alone is continual and incessant, and it fills all its pupils and disciples with famous and most beautiful doctrines." When Moses heard this he did not cease from his desire, but he still burned with a longing for the understanding of invisible things." (Philo, De Specialibus Legibus 1,47-49)

Philo: "Do not, however, think that the living God, he who is truly living, is ever seen so as to be comprehended by any human being"

"II. (7) Do not, however, think that the living God, he who is truly living, is ever seen so as to be comprehended by any human being; for we have no power in ourselves to see any thing, by which we may be able to conceive any adequate notion of him; we have no external sense suited to that purpose (for he is not an object which can be discerned by the outward sense), nor any strength adequate to it: therefore, Moses, the spectator of the invisible nature, the man who really saw God (for the sacred scriptures say that he entered "into the Darkness,"{3}{#ex 20:21.} by which expression they mean figuratively to intimate the invisible essence), having investigated every part of every thing, sought to see clearly the much-desired and only God; (8) but when he found nothing, not even any appearance at all resembling what he had hoped to behold; he, then, giving up all idea of receiving instruction on that point from any other source, flies to the very being himself whom he was seeking, and entreats him, saying, "Show my thyself that I may see thee so as to know Thee."{4}{#ex 33:13.} But, nevertheless, he fails to obtain the end which he had proposed to himself, and which he had accounted the most all-sufficient gift for the most excellent race of creation, mankind, namely a knowledge of those bodies and things which are below the living God. (9) For it is said unto him, "Thou shalt see my back parts, but my face shall not be beheld by Thee."{5}{#ex 33:23.} As if it were meant to answer him: Those bodies and things which are beneath the living God may come within thy comprehension, even though every thing would not be at once comprehended by thee, since that one being is not by his nature capable of being beheld by man. (10) And what wonder is there if the living God is beyond the reach of the comprehension of man, when even the mind that is in each of us is unintelligible and unknown to us? Who has ever beheld the essence of the soul? the obscure nature of which has given rise to an infinite number of contests among the sophists who have brought forward opposite opinions, some of which are inconsistent with any kind of nature. (11) It was, therefore, quite consistent with reason that no proper name could with propriety be assigned to him who is in truth the living God. Do you not see that to the prophet who is really desirous of making an honest inquiry after the truth, and who asks what answer he is to give to those who question him as to the name of him who has sent him, he says, "I am that I Am,"{6}{#ex 3:14.} which is equivalent to saying, "It is my nature to be, not to be described by name:" (12) but in order that the human race may not be wholly destitute of any appellation which they may give to the most excellent of beings, I allow you to use the word Lord as a name; the Lord God of three natures--of instruction, and of holiness, and of the practice of virtue; of which Abraham, and Isaac, and Jacob are recorded as the symbols. For this, says he, is the everlasting name, as if it has been investigated and discerned in time as it exists in reference to us, and not in that time which was before all time; and it is also a memorial not placed beyond recollection or intelligence, and again it is addressed to persons who have been born, not to uncreated natures. (13) For these men have need of the complete use of the divine name who come to a created or mortal generation, in order that, if they cannot attain to the best thing, they may at least arrive at the best possible name, and arrange themselves in accordance with that; and the sacred oracle which is delivered as from the mouth of the Ruler of the universe, speaks of the proper name of God never having been revealed to any one, when God is represented as saying, "For I have not shown them my Name;"{7}{#ex 6:3.} for by a slight change in the figure of speech here used, the meaning of what is said would be something of this kind: "My proper name I have not revealed to them," but only that which is commonly used, though with some misapplication, because of the reasons abovementioned. (14) And, indeed, the living God is so completely indescribable, that even those powers which minister unto him do not announce his proper name to us. At all events, after the wrestling match in which the practicer of virtue wrestled for the sake of the acquisition of virtue, he says to the invisible Master, "Tell me thy Name;"{8}{#ge 32:29.} but he said, "Why askest thou me my name?" And he does not tell him his peculiar and proper name, for says he, it is sufficient for thee to be taught my ordinary explanations. But as for names which are the symbols of created things, do not seek to find them among immortal natures." (Philo, De Mutatione Nominum 7-14) 

"μὴ μέντοι νομίσῃς τὸ ὄν, ὅ ἐστι πρὸς ἀλήθειαν ὄν, ὑπ’ ἀνθρώπου τινὸς καταλαμβάνεσθαι. ὄργανον γὰρ οὐδὲν ἐν ἑαυτοῖς ἔχομεν, ᾧ δυνησόμεθα ἐκεῖνο φαντασιωθῆναι, οὔτ’ αἴσθησιν – αἰσθητὸν γὰρ οὐκ ἔστιν – οὔτε νοῦν. Μωυσῆς οὖν ὁ τῆς ἀειδοῦς φύσεως θεατὴς [καὶ θεόπτης] – εἰς γὰρ τὸν γνόφον φασὶν αὐτὸν οἱ θεῖοι χρησμοὶ εἰσελθεῖν (Exod. 20, 21), τὴν ἀόρατον καὶ ἀσώματον οὐσίαν αἰνιττόμενοι – πάντα διὰ πάντων ἐρευνήσας ἐζήτει τὸν τριπόθητον καὶ μόνον ἀγαθὸν τηλαυγῶς ἰδεῖν.   8. ἐπεὶ δ’ οὐδὲν εὕρισκεν, ἀλλ’ οὐδὲ ἐμφερῆ τινα ἰδέαν τῷ ἐλπιζομένῳ, τὴν ἀπὸ τῶν ἄλλων διδασκαλίαν ἀπογνοὺς ἐπ’ αὐτὸ καταφεύγει τὸ ζητούμενον καὶ δεῖται λέγων· “ἐμφάνισόν μοι σεαυτόν, γνωστῶς ἴδω σε” (Exod. 33, 13)· καὶ ὅμως ἀμοιρεῖ τῆς προθέσεως, αὐταρκεστάτης δωρεᾶς τῷ θνητῶν ἀρίστῳ γένει νομισθείσης τῆς <τῶν> μετὰ τὸ ὂν σωμάτων τε ὁμοῦ καὶ πραγμάτων ἐπιστήμης.   9. λέγεται γάρ· “ὄψει τὰ ὀπίσω μου, τὸ δὲ πρόσωπόν μου οὐκ ὀφθήσεταί σοι” (ibid. 23), ὡς τῶν ὅσα μετὰ τὸ ὂν σωμάτων τε ὁμοῦ καὶ πραγμάτων εἰς κατάληψιν ἐρχομένων, εἰ καὶ μὴ πάντα ἤδη καταλαμβάνεται, μόνου δ’ ἐκείνου μὴ πεφυκότος ὁρᾶσθαι.   10. καὶ τί θαυμαστόν, εἰ τὸ ὂν ἀνθρώποις ἀκατάληπτον, ὁπότε καὶ ὁ ἐν ἑκάστῳ νοῦς ἄγνωστος ἡμῖν; τίς γὰρ ψυχῆς οὐσίαν εἶδεν; ἧς ἡ ἀδηλότης μυρίας ἔριδας σοφισταῖς ἐγέννησεν ἐναντίας εἰσηγουμένοις γνώμας ἢ καὶ ὅλοις γένεσιν ἀντιστατούσας.   11. ἦν οὖν ἀκόλουθον τὸ μηδ’ ὄνομα κύριον ἐπιφημισθῆναι δύνασθαι τῷ ὄντι πρὸς ἀλήθειαν. οὐχ ὁρᾷς ὅτι φιλοπευστοῦντι τῷ προφήτῃ, τί τοῖς περὶ τοῦ ὀνόματος αὐτοῦ ζητοῦσιν ἀποκριτέον, φησὶν ὅτι “ἐγώ εἰμι ὁ ὤν” (Exod. 3, 14), ἴσον τῷ εἶναι πέφυκα, οὐ λέγεσθαι;   12. τοῦ δὲ μὴ παντάπασιν ἀμοιρῆσαι τὸ τῶν ἀνθρώπων γένος προσρήσεως τοῦ ἀρίστου, δίδωσι καταχρῆσθαι ὡς ἂν ὁ ὢν ὀνόματι τοιούτῳ· “κύριος ὁ θεὸς” τῶν τριῶν φύσεων, διδασκαλίας, τελειότητος, ἀσκήσεως, ὧν σύμβολα Ἀβραάμ, Ἰσαάκ, Ἰακὼβ ἀναγράφεται. “τοῦτο γάρ μου” φησίν “ὄνομα αἰώνιον” ὡς ἂν ἐν τῷ καθ’ ἡμᾶς αἰῶνι ἐξεταζόμενον, οὐκ ἐν τῷ πρὸ αἰῶνος, “καὶ μνημόσυνον”, οὐ τὸ πέρα μνήμης καὶ νοήσεως ἱστάμενον, καὶ πάλιν “γενεαῖς” (ibid. 15), οὐ φύσεσιν ἀγενήτοις.   13. καταχρήσεως γὰρ ὀνόματος θείου δεῖ τοῖς εἰς τὴν θνητὴν γένεσιν ἐλθοῦσιν, ἵν’, εἰ καὶ μὴ πράγματι, ὀνόματι γοῦν προσερχόμενοι ἀρίστῳ κατ’ αὐτὸ κοσμῶνται. δηλοῖ δὲ καὶ λόγιον ἐκ προσώπου θεσπισθὲν τοῦ τῶν ὅλων ἡγεμόνος περὶ τοῦ μηδενὶ δεδηλῶσθαι τὸ ὄνομα αὐτοῦ κύριον. “ὤφθην” φησί “πρὸς Ἀβραὰμ καὶ Ἰσαὰκ καὶ Ἰακὼβ θεὸς ὢν αὐτῶν, καὶ τὸ ὄνομά μου κύριον οὐκ ἐδήλωσα αὐτοῖς” (Exod. 6, 3). τοῦ γὰρ ὑπερβατοῦ μετατεθέντος ἑξῆς ἂν τοιοῦτος εἴη λόγος· “ὄνομά μου τὸ κύριον οὐκ ἐδήλωσα αὐτοῖς”, ἀλλὰ τὸ ἐν καταχρήσει διὰ τὰς εἰρημένας αἰτίας.   14. οὕτω μέντοι τὸ ὂν ἄῤῥητόν ἐστιν, ὥστ’ οὐδὲ αἱ ὑπηρετούμεναι δυνάμεις κύριον ὄνομα ἡμῖν λέγουσι· μετὰ γοῦν τὴν πάλην, ἣν ὑπὲρ κτήσεως ἀρετῆς ὁ ἀσκητὴς ἐπάλαισε, φησὶ τῷ ἀοράτῳ ἐπιστάτῃ· “ἀνάγγειλόν μοι τὸ ὄνομά σου”, ὁ δὲ εἶπεν· “ἵνα τί τοῦτο ἐρωτᾷς τὸ ὄνομά μου;” (Gen. 32, 29), καὶ οὐ μηνύει τὸ ἴδιον καὶ κύριον. ἀπόχρη γάρ σοι, φησίν, ὠφελεῖσθαι κατὰ τὰς ἐμὰς εὐφημίας, τὰ δὲ γενητῶν σύμβολα, ὀνόματα, μὴ ζήτει παρὰ φύσεσιν ἀφθάρτοις·"