If your past has been holding you back, God can fix it.
When Israel was freed from the slavery of Egypt, Pharaoh sent his army to take them back. When the army was about to overtake them, God Himself stood between them as a pillar of smoke. Shortly afterward, God destroyed the army (see Ex. 14).
The Bible says in Romans 8:28, "And we know that all things work together for good ..." This verse is not confined to what may be going on in our lives at present---it also includes our past.
So how do we bring God to move behind us? The Bible says in Isaiah 58:7-8 (NLT), "Share your food with the hungry, and give shelter to the homeless. Give clothes to those who need them, and do not hide from relatives who need your help. "Then your salvation will come like the dawn, and your wounds will quickly heal. Your godliness will lead you forward, and the glory of the Lord will protect you from behind."
When we focus on the will of God in our lives, God leads us where to go, and takes care of our past.
Perhaps you have been plagued with sickness, a wayward child, financial trouble, or a broken marriage. Whatever it might be that holds you back, God will use it to produce something better!
No matter what the situation is, God wants to fix it. Isaiah said, "your godliness will lead you forward" (Is. 58:8 above). When we are good to others, we advance forward and God takes care of our past.