Juan 13:16

Jesus again introduced a statement with a strong asseveration to indicate its importance. He put it in the form of an aphorism (cf. John 15:20; Matthew 10:24; Luke 6:40; Luke 22:37). An aphorism is a concise definition or statement of a principle. By common consent slaves occupy an inferior role to that of their masters, and messengers (Gr. apostolos) do the same to those who send them. This, by the way, is the only occurrence of apostolos in the fourth Gospel. Jesus was contrasting roles, not essential worth. His point was that no disciple of His should think it beneath him or her to serve others since He, the master and sender, had humbled Himself to serve.

Jesus had repeatedly referred to the fact that the Father had sent Him and that He had come from the Father. Likewise He would send the disciples (John 20:21).