Jesus saith unto them, My meat is to do the will of Him that sent Me, and to finish His work… And he that reapeth receiveth wages, and gathereth fruit unto life eternal: that both he that soweth and he that reapeth may rejoice together.-John 4:34, 36

Now you generally know when a man’s heart is in his work, by the joy he feels in it. You see some preachers go up into their pulpits as though they were going to be roasted at the stake; and they read their sermons through as if they were making their last dying speech and confession. What do you think they call it?-why, doing their duty. True ministers call preaching a pleasure, not a duty. It is a delight to stand up to tell to others the way of salvation and to magnify Christ. But mere hirelings cannot go higher than the idea of doing their duty when they are telling out this glorious tale. Jesus Christ was none of these. “My meat is” He said, “to do the will of Him that sent Me.” The only times that Jesus ever smiled and rejoiced are the times when He was in the midst of poor sinners. At that time “Jesus rejoiced in spirit, and said, I thank Thee, O Father, Lord of heaven and earth, that Thou hast hid these things from the wise and prudent, and hast revealed them unto babes.” Let Him see a penitent, let Him hear the groan of a sinner mourning over his evil way, let Him discern a tear trickling down the cheek of one of His hearers, and Jesus Christ begins to be glad, and the Man of Sorrows wears a smile for a moment upon that pale and sorrowful face. At all times there is a travailing in birth for souls: He is only happy when He sees the family of God enlarged.~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0302.cfm