Final answer:
John 4:37 completes as 'For in this the saying is true: One sows and another reaps,' referring to collaborative efforts in God's work.
Step-by-step explanation:
According to John 4:37, the verse completes with "For in this the saying is true: One sows and another reaps." This verse is discussing the idea of collaboration in the work of God's kingdom, where different people play various roles but all contribute to the same goal. In the context of the chapter, Jesus is speaking to His disciples about the spiritual harvest, suggesting that while one person may plant the seeds of faith, another may be the one to reap or harvest the spiritual fruits that come from it.