What we focus on is magnified, focus on your problems ,you will only see how big it is and how you can't overcome it. But if you focus on God then, you realize how big your God is and how much His love can help you overcome your challenge.
This faith and focus on God develops a inner momentum in you, strong enough to propel you to victory.
Learn to rely on God at all time just like King David in the Bible .
There's no such thing as inner momentum.