…out of weakness were made strong… – Hebrews 11:34

…My grace is sufficient for thee: for My strength is made perfect in weakness. – 2 Corinthians 12:9

“Yes,” says one, “I own that it is an urgent service to make known to others what the Lord has done for me: but, somehow, I cannot discharge my conscience by fully doing as I would. I tried the other day to say a good word, and I am afraid that I made a failure of it. I stammered a good deal, and I said little that I thought to say, and some things which seemed to weaken what I did say. I resolved, the other day, that I would see a man whom I had known, and tell him that I was a changed character; but when I reached his house, I drifted into other talk, and went the way in which he led me. I could not come to the point.” Many would make a similar confession if they made a clean breast of it. Many of the truest children of God are at first possessed by a dumb spirit; and it needs the Lord Jesus to cast it out. But do you not think that we are too apt to attempt to spread the gospel in our own strength; and need we wonder if we break down? If we were by faith to begin, humbly waiting upon the Lord for words, and taking hold upon divine strength, might we not accomplish far more than we now do? Dear friend, would you like to do something great for God? Have you heard the motto of our early missionaries: “Attempt great things for God”? Does that thought burn within your heart? Do you long to be of some use? “Oh, yes,” says one, “I would attempt great things for God, but I am terribly weak.” Make the attempt by faith in God; for it is written, “Out of weakness were made strong.” If you feel incapable, throw yourself upon the infinite capacity of God. So long as you are willing to be used, so long as God has given you an anxiety and travail of spirit for the souls of others, you need not fear; but may with faith get to work in all your feebleness, for as your day your strength shall be. Has not the Lord said, “My grace is sufficient for thee: for My strength is made perfect in weakness”? And is not that word true? ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2209.cfm