And we know that all things work together for good to them that love God, to them who are the called according to his purpose. For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren. Romans 8:28-29
Just about everyone knows Romans 8:28. You can find it on cards, plaques, pictures, etc., but people often fail to go on and read the next verse. Verse twenty-eight says that God has a purpose. Verse twenty-nine tells us what the purpose is.
This passage is written to saved people. God did not have a purpose or your life until He knew you. That means you are born-again. You do not just know of Him, but you KNOW Him. It is the same picture as the Bible says in Genesis that "Adam knew Eve his wife". They two became one. We become one in Christ when we are saved. The Bible says many will stand before the Lord and He will say, "...I never knew you: depart from me, ye that work iniquity." That does not mean that He chose to forget them. It means there was never a relationship. An example of this is in Luke sixteen and the account of the rich man and Lazarus. The Bible does not tell us the rich man's name. That is because he was a lost man who ended up in Hell. The account does tell us Lazarus' name because he was saved and ended up in Paradise.
When we begin a relationship with Christ (salvation), He knows us. Many are afraid of the word "predestinate" in verse twenty-nine. Do not be afraid of the word. It is a good word. There are many who prevert the meaning of it and teach that God predetermined who would go to Heaven and who would go to Hell. That heresy is not supported in all of Scripture. Read on! God predetermined that those He KNOWS be "conformed to the image of His Son". You are only predestinated if you are saved. Lost people are not predestinated.
Look for a moment at I John 3:1-2, "Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not. Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is."
The Bible does not say that we will look like Him, it says we will BE like Him. He is perfectly righteous and that is His purpose for us. When God the Father looks at us, He sees Christ's righteousness. His purpose for us is for our standing in Christ to match our state in Christ. That others may see what is on the inside. So when you get saved, the Holy Spirit is working in you what God has predetermined...to make you be like Christ! John 17:21-23 says, "That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me. And the glory which thou gavest me I have given them; that they may be one, even as we are one: I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me." God is now working His purpose in my life, not to make me more righteous, but to make others see that I am righteous.