The following is an excerpt from Wayne Grudem, Systematic Theology (highly recommended). In the chapter on the Trinity, there is a long section on the the Old Testament evidence for the doctrine. In it we find on pages 229-230 these following remarks on Proverbs 8:22-31.

One of the most disputed Old Testament texts that could show distinct personality for more than one person is Proverbs 8:22-31. Although the earlier part of the chapter could be understood as merely a personification of "wisdom" for literary effect, showing wisdom calling to the simple and inviting them to learn, vv. 22-31, one could argue, say things about "wisdom" that seem to go far beyond mere personification. Speaking of the time when God created the earth, "wisdom" says, "Then I was the craftsman at his side. I was filled with delight day after day, rejoicing always in his presence, rejoicing in his whole world and delighting in mankind" (Prov. 8:30-31 NIV). To work as a "craftsman" at God's side in the creation suggests in itself the idea of distinct personhood, and the following phrases might seem even more convincing, for only real persons can be "filled with delight day after day" and can rejoice in the world and delight in mankind.[7]

But if we decide that "wisdom" here really refers to the Son of God before he became man, there is a difficulty. Verses 22-25 (RSV) seem to speak of the creation of this person who is called "wisdom":

 
   The LORD created me at the beginning of his work, 
         the first of his acts of old.

   Ages ago I was set up, 
         at the first, before the beginning of the earth.

   When there were no depths I was brought forth, 
         when there were no springs abounding with water.

   Before the mountains had been shaped, 
         before the hills, I was brought forth.

Does this not indicate that this "wisdom" was created?

In fact, it does not. The Hebrew word that commonly means "create" (bara') is not used in verse 22; rather the word is qanah, which occurs eighty-four times in the Old Testament and almost always means "to get, acquire." The NASB is most clear here: "The Lord possessed me at the beginning of his way" (similarly KJV). (Note this sense of the word in Gen. 39:1; Ex. 21:2; Prov. 4:5,7; 23:23; Eccl. 2:7; Isa. 1:3 ["owner"].) This is a legitimate sense and, if wisdom is understond as a real person, would mean only that God the Father began to direct and make use of the powerful creative work of God the Son at the time creation began: the Father summoned the Son to work with him in the activity of creation. The expression "brought forth" in verses 24 and 25 is a different term but could carry a similar meaning: the Father began to direct and make use of the powerful creative work of the Son in the creation of the universe.

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7. In response to these arguments, one could argue that there are similarly detailed personifications of Wisdom in Prov. 8:1-12 and 9:1-6, and of foolishness in Prov. 9:13-18, and no interpreter understands these to be actual persons. Therefore, Prov. 8:22-31 does not represent an actual person either. This argument seems convincing to me, but I have included the following paragraph because Prov. 8:22-31 has a long history of interpreters who think it refers to God the Son.

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