Then did he see it - That is, then did he see wisdom. When in the work of creation he gave laws to the rain and the thunder storm; when he weighed out the winds and measured out the waters, then he saw and understood the principles of true wisdom. There is a remarkable similarity between the expression here and Proverbs 8:27-30, "When he prepared the heavens, I (wisdom) was there; when he set a compass upon the face of the depth; when he established the clouds above; when he strengthened the foundations of the deep; when he gave to the sea his decree, that the waters should not pass his commandment; when he appointed the foundations of the earth; then I was by him as one brought up with him; I was daily his delight, rejoicing always before him."
And declare it - Margin, "number." The word (ספר sâphar) means, however, rather to "declare," or to "narrate;" and the idea is, that even then he made known to intelligent beings the true principles of wisdom, as consisting in the fear of the Lord, and in suitable veneration for the Most High. "In what way" this was made known, Job does not say; but there can be no doubt of the fact to which he adverts, that even in his time the great principles of all real wisdom were made known to created intelligences, as consisting in profound veneration of God, in a willingness to bow under his dispensations, and to confide in him.
He prepared it - Made it a matter of "thought" and "inquiry" to find out what was real wisdom, and communicated it in a proper way to his creatures. The idea is, that it was not the result of chance, nor did it spring up of its own accord, but it was a matter of "intelligent investigation" on the part of God to know what constituted true wisdom. Probably, also, Job here means to refer to the attempts of man to investigate it, and to say that its value was enhanced from the fact that it had even required "the search of God" to find it out. Beautiful eulogiums of Wisdom may be seen in the Apocryphal book Ecclesiasticus, of which the following is a specimen:
Wisdom shall praise herself,
And shall glory in the midst of her people.
In the congregation of the Most High shall she open her mouth,
And triumph before his power.
I came out of the mouth of the Most High,
And covered the earth as a cloud.
I dwell in high places,
And my throne is in a cloudy pillar.
I alone compassed the circuit of heaven,
And walked in the bottom of the deep.
In the waves of the sea, and in all the earth,
And in every people and nation, I got a possession.
He created me from the beginning, before the world,
And I shall never fall. Ecclus. 24

Then did he see it, and declare it - When he had finished all his creative operations, and tried and proved his work, חקרה chakarah, investigated and found it to be very good; then he gave the needful revelation to man; for,

Then did he see it, and declare it,.... His own wisdom, when he made and executed his decrees concerning rain, lightning, and thunder; he saw it in himself, and as it appeared in the works of his hands, which he looked on and approved of, and saw that all was very good; and he declared it to others, by his works of nature and providence; for they declare the glory of God, and particularly the glory of his wisdom:
he prepared it, yea, and searched it out; he prepared it in his counsels, according to which he wrought all things in the creation, and still does in Providence; and his searching out denotes his perfect knowledge of it, and the way and course of it, or he takes with it, though it is unsearchable, and past finding out by us. Mr. Broughton understands this of a person, as do some others, even Christ, the Wisdom of God; rendering the words, "then he saw her, and showed her", &c. and so the passages in Proverbs 8:27, may be a comment on these words and the foregoing; for when the above decrees were formed in the divine mind, then he "saw" his Wisdom, his Logos, his eternal Son; for he was by him, and with him, and in him, lying in his bosom; he looked at him in creation, and made man after his image, the idea he had formed of his human nature, and made all things for his sake; and he viewed him with the utmost delight and pleasure, as being the express image of his person; he declared him to be his only begotten Son, saying, "this day I have begotten thee", Psalm 2:7; be made him known to the angels, as the Targum here expresses it, and what he designed to do by him, and with him; which occasioned the revolt of many of them from him; and he declared him to Adam as soon as there was an opportunity and occasion for it; he prepared him in his eternal purposes to be the Redeemer and Saviour of his people, to be the Head of the church, and the Judge of quick and dead; he searched him out in his infinite wisdom, and found him, singled him out, laid help on him with his holy oil anointed him, and appointed him to be the ransomer of his chosen ones, Job 33:24.

declare--manifest her, namely, in His works (Psalm 19:1-2). So the approval bestowed by the Creator on His works (Genesis 1:10, Genesis 1:31); compare the "rejoicing" of wisdom at the same (Proverbs 8:30; which UMBREIT translates; "I was the skilful artificer by His side").
prepared--not created, for wisdom is from everlasting (Proverbs 8:22-31); but "established" her as Governor of the world.
searched . . . out--examined her works to see whether she was adequate to the task of governing the world [MAURER].

It - Wisdom, which is the subject of the present discourse. This God saw within himself; he looked upon it in his own mind, as the rule by which he would proceed in the creation and government of all things. Declare - Or reveal it. Prepared - He had it in readiness for doing all his works, as if he had been for a long time preparing materials for them. So it is a speech of God after the manner of men. Searched - Not properly; for so searching implies ignorance, and requires time and industry, all which is repugnant to the Divine perfections; but figuratively, he did, and doth, all things with that absolute and perfect wisdom, so exactly, and perfectly, as if he had bestowed a long time in searching, to find them out.