Have you ever been at a point in your life where you did your best but your best wasn't good enough? Like you gave it a hundred percent effort, but the results were a jaw-dropping fail? I know that's frustrating, but I'm here to encourage you with two words: keep going.
Going on when you're tempted to stop
Friends, it's always tempting to give up doing what is right, what is good, and what is just. You've given all you've got to encourage others, but they're still discouraged. You've spent a fortune in reaching out to others with the Gospel but they keep staying away from you. You've pushed people to work harder to succeed, but they remain lazy.
I know that will feel bad, even drive some of us crazy, but let's not allow failures to discourage us. We are told,
"Do not be deceived, God is not mocked; for whatever a man sows, that he will also reap... And let us not grow weary while doing good, for in due season we shall reap if we do not lose heart. Therefore, as we have opportunity, let us do good to all, especially to those who are of the household of faith." (Galatians 6:7, 9-10)
Keep on keeping on
Friends, when you've given all that you've got for a purpose that God had in mind for you, don't worry. He knows what you've done, and He knows the intention of your heart. Consider how He encouraged Paul, who was somehow limited by a problem that he had:
"I (Paul) asked the Lord three times that this (thorn in my flesh) might depart from me. But He said to me, "My grace is sufficient for you, for My strength is made perfect in weakness." Therefore most gladly I will boast in my weaknesses, that the power of Christ may rest upon me." (see 2 Corinthians 12:8-9, emphasis mine)
Paul initially saw his "thorn in the flesh" as some sort of problem that limited him, but that changed when God promised him that His grace will be sufficient in his weakness.
This same Paul is the man who encourages us,
"Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your labor is not in vain in the Lord." (1 Corinthians 15:58)
When what you've done isn't enough, count on God to do what you can't. Do your best according to God's instructions and let Him handle the things that you cannot. Be steadfast and keep doing the will of God.