A.T. Robertson 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)

Already he that reapeth receiveth wages (ηδη ο θεριζων μισθον λαμβανε). The spiritual harvester can gather his harvest without waiting four months. Jesus is reaping a harvest right now by the conversion of this woman. The labourer is worthy of his hire (Luke 10:7; 2 Timothy 2:6). John does not use μισθος (reward) again, but καρπος (15:2-16), "fruit for life eternal" (cf. 4:14).

That he that soweth and he that reapeth may rejoice together (ινα ο σπειρων ομου χαιρη κα ο θεριζων). Final use of ινα with present active subjunctive of χαιρω, to rejoice, in the singular with ο σπειρων (the sower) and to be repeated with ο θεριζων (the reaper). The adverb ομου (together) elsewhere in N.T. only 20:4; 21:2; Acts 2:1. Usually considerable time passes between the sowing and the reaping as in verse 35. Amos (Amos 9:13) spoke of the time when "the ploughman shall overtake the reaper" and that has happened here with the joy of the harvest time (Isaiah 9:3). Jesus the Sower and the disciples as the reapers are here rejoicing simultaneously.