“This” (NIV) is actually plural “these” or “these things” which may indicate that all of the commands Jesus had spoken that evening were for the single purpose of the disciples engaging in love for each other.

Jesus’ command to love each other is a repetition of (13:34; 15:12). This very night the disciples have been guilty of jealousy and non-loving behavior (Luke 22:24; John 13:5,15), but friends of a Friend should themselves be friends. (Maclaren) Christians are knit together by the bond of friendship with Jesus and we need to act like friends to each other by loving each other for our mutual Friend’s sake.

John 13:34  “A new command I give you: Love one another. As I have loved you, so you must love one another.

John 15:12  My command is this: Love each other as I have loved you.

Luke 22:24  Also a dispute arose among them as to which of them was considered to be greatest.

John 13:5  After that, he poured water into a basin and began to wash his disciples’ feet, drying them with the towel that was wrapped round him.

John 13:15  I have set you an example that you should do as I have done for you.