The only thing that limits God is our faith.  Small faith small things, large faith then God can do more.   But this is balanced by obedience.  In the Christian life obedience is required, but understanding “why” is optional.  Sometime we do not understand things until later.

So in brief we limit God by our lack of faith, lack of prayer and lack of obedience to Him.

From Hebrews 12 – …let us run with endurance the race that is set before us, 2 looking to Jesus, the founder and perfecter of our faith.