"...yea, I have spoken it, I will bring it to pass; I have purposed it, I will also do it.” -Isaiah 46:11
There are people who go through life beginning things. They have wonderful ideas; they just never seem able to see them through. God is not one of those people. On the other hand, some people lack any real initiative and would rather take someone else's idea and run with it. This is not a description of God, either. He took the initiative and spoke the world into existence, and you can count on Him seeing it through to the end. He purposed to provide an all-sufficient redemption for Adam's fallen race, and when Jesus died on the Cross, He proclaimed, "It is finished!"
Of all the projects God has taken on, you and I are not at all the least significant. Paul has told us in Philippians 1:6 that we can be confident of this: "[H]e which hath begun a good work in you will perform it until the day of Jesus Christ." It was God's idea (not yours) to begin this good work in you. He took the initiative; you merely responded. And what He begins, He finishes. We are His workmanship (Eph. 2:10), and He will not stop until the work is done.
You and I have been called to do something in this life, as well. It may be on stage, in the wings, or a little of both. But one way or another, it’s our calling. It is based partly on our ability, but mostly on the basis of what He knew would be our availability. And if we mean business, so does God. If we have a mind to finish, He is prepared to see that we do. For He promised in First Thessalonians 5:24, "Faithful is he that calleth you, who also will do it."
God has said of Himself, "I am Alpha and Omega, the beginning and the ending.." (Rev. 1:8). That says who He is...and what He does. I am part of what He's doing. He has purposed to make me perfect, and one day, God—the Great Finisher—will finish the job!