Question:

Did God become man so that He could better understand the temptations and struggles we go through?

Answer:

The "so that" and "better understand" are crucial here. God did not need to become man to know and understand (let alone "better understand") our human struggles, as the testimony of pre-incarnation Scripture makes clear: 1 Samuel 2:3, 16:7, 1 Kings 8:39, 1 Chronicles 28:9, Psalm 1:6, 11:4f, 14:2, 33:13ff, 34:15f, 102:19f, 139:1-16, Prov.15:3, 16:2, 24:12, Isaiah 40:12-17 (passages I could find rather quickly, I'm sure there are many more of this sort). It is man who lacks understanding (Psalm 14:4); the Lord's understanding of us and our hearts is perfect and complete. As the Apostle Paul says, "Oh the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments and unfathomable His ways!" (Rom.11:33) - He who "will judge the secrets of men through Jesus Christ" (2:16).

The stated purpose of our Lord's coming from heaven and taking our human nature was "to save His people from their sins" (Matthew 1:21), to "give His life a ransom for many" (Mark 10:45), "to seek and to save what was lost" (Luke 19:10), to reveal the Father (John 1:19, 14:8,9), to "do the will of Him who sent Me ... that of all that He has given Me I lose nothing, but raise it up on the last day" (John 6:38f), to bear the sins of many, to destroy the works of the devil, etc., etc. I am not aware of any passage that says that the Son became man in order to understand better His creature.

Having said all of that, however, Hebrews does point us to one of the great encouragements that belongs to believers in Christ because of His incarnation. We now may know that our great High Priest in heaven does have a perfect understanding of our weakness and temptations (4:15, cf. 5:7-10). We should never say that there was something lacking in God's perfect wisdom and understanding. However, when God the Son took our flesh and blood, His understanding became like ours in addition to what it was before; that is, He now understood from experience, from "inside" our human nature. This is not presented as a purpose of His coming in our nature, but as a blessing to us in consequence of His coming in our nature.

Of course, as nothing that happens lies outside of the eternal and sovereign plan of God, even this was planned and could therefore be said to have been a purpose of the incarnation. But the point of it is not that God sought out a way of improving His understanding of His creature man, but rather that God condescended to grant to us this wonderful assurance - namely, that we can know that when we have sinned or are struggling with a temptation too great for our strength, at the Father's right hand His Son is interceding for us with a knowledge and sympathy (fellow-feeling) of our experience that is like our own - except without sin - praise Him!