Here are a few scriptures about doing your best.
I have fought the good fight. I have completed the race. I have kept the faith.
You know that in a race all the runners run but only one wins the prize, don’t you? You must run in such a way that you may be victorious.
Commit your work to the Lord, then it will succeed.
Whatever you do, work heartily, as for the Lord and not for men, knowing that from the Lord you will receive the inheritance as your reward. You are serving the Lord Christ.
Do your best on your walk of faith. If God tells you to do something work hard and do your best. God will do all the things you can’t do.