Albert Barnes Commentary John 4:36

"He that reapeth receiveth wages, and gathereth fruit unto life eternal; that he that soweth and he that reapeth may rejoice together." — John 4:36 (ASV)

He that reapeth. He who 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 will be so with those who labour in the ministry—he will not allow them to go unrewarded. See Daniel 12:3; Matthew 19:28.

Gathereth fruit unto life eternal. Converts souls, who will inherit eternal life. The harvest is not temporary, like gathering grain, but will 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, will rejoice with the minister of the gospel who may gather in the harvest, and both join in giving all the praise to God.