Isaiah says that when God restores Israel, He will go before them and behind them (Is. 52:12). The first Advent of God was the incarnation, when God went before us, leading us out of the dungeon of sin and death. The final Advent of God at the end of history is when God comes up behind us, as our rearguard, finishing what was begun at the incarnation.
In other words, from Advent to Advent from first coming to second coming, God is the beginning and the end, the first and the last, the alpha and the omega.
Or, in other words, we are all Calvinists after all. The incarnation is God’s decisive, efficacious act of regeneration for the whole world. Because we could not prepare ourselves for Him, He came in order to prepare us for Him. Then He sent His Spirit to comfort, strengthen, and cheer us, continuing the work that was begun in us. And He will come again and finish what He started.
God came in Christ in order to make us into a place where the Spirit could dwell in order to make this world a place that could bear the weight of heaven when it arrives at the end. It’s all of grace from first to last because it’s all of Jesus who is the first and the last. He was and is and is to come.