So he departed thence, and found Elisha the son of Shaphat… -1 Kings 19:19 

Behold, I will make thee a new sharp threshing instrument having teeth… -Isaiah 41:15

Elijah was to go back to anoint his successor. If Elijah flees, and if Elijah at length is taken up to heaven, yet Elisha shall succeed him. Perhaps there may be a brother here who is in the state I have described who does not know what God has in store for him. You are to call into the Christian ministry a brother that shall do greater than you have, you shall light a greater candle than your own. Oh! what joy Elijah must have had when he felt there would be someone to take up his work! You have not, my dear brother, yet called out for your master the man the Lord means to call. What a happy man he must have been who was the means of the conversion of Whitefield or Jonathan Edwards, or some great missionary of the cross. You may be that, in that little village-in that back slum. Go thou back then. What doest thou here, Elijah? What doest thou here? The Master’s voice speaks to thee. Go to thy closet, and get fresh strength from on high, and then go back to thy difficulties-go back to thy self-denials, go back to all thy service with a good heart and true. “Fear not thou worm Jacob; I will help thee, saith the Lord.” Arise, thou worm, and thresh the mountain, for “I will make thee a new sharp threshing instrument having teeth.” I have delivered the message. It is to somebody, I know not to whom… ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/3498.cfm