Albert Barnes on John 4:36

He that reapeth. He that gathers the harvest, or he who so preaches that souls are converted to Christ.

Receiveth wages. The labourer in the harvest receives his hire. Jesus says it shall be thus with those who labour in the ministry--he will not suffer them to go unrewarded. See Dan 12:3, Mt 19:28.

Gathereth fruit unto life eternal. Converts souls, who shall inherit eternal life. The harvest is not temporary, like gathering grain, but shall result in eternal life.

That both he that soweth, &c. It is a united work. It matters little whether we sow the seed or whether we reap the harvest. It is part of the same work, and whatever part we may do, we should rejoice. God gives the increase, while Paul may plant and Apollos water. The teacher in the Sunday-school, who sows the seed in early life, shall rejoice with the minister of the gospel who may gather in the harvest, and both join in giving all the praise to God.

(w) "gathereth" Rom 6:22 (x) "both he that soweth" 1Cor 3:5-9