John 13:31-35 Therefore, when he was gone out, Jesus said, Now is the Son of man glorified, and God is glorified in him. If God be glorified in him, God shall also glorify him in himself, and shall straightway glorify him. Little children, yet a little while I am with you. You shall seek me: and as I said unto the Jews, Whither I go, you cannot come; so now I say to you. A new commandment I give unto you, That you love one another; as I have loved you, that you also love one another. By this shall all men know that you are my disciples, if you have love one to another.
The 29th New Testament prophecy in John that is fulfilled: Jesus said that He was glorified by being appointed to save the world and the Father is glorified in Him saving the world. The Father and Jesus are glorified together in seeing Their ruined work redeemed and restored.
Jesus warned that He was there with them for only a short time and then they will seek Him, but cannot follow where He goes. Jesus was with them for one more day before the crucifixion, and He remained dead for 3 whole days. Then they could see Him for 40 more days and no more after that (Mat. 12:40; Acts 1:3, 11). He said this to the Jews (John 7:34; 8:21), and to His disciples: when He did finally go they cannot follow Him, but He will come back for them at a later time (John14:1-3).
‘New’ the Greek word kainos meaning renewed. This is the same as the old commandment in Leviticus 19:18, “Thou shall love thy neighbour as thyself.” The renewed commandment here has an additional part, “as I have loved you.” Christ more than fulfilled the Mosaic precept. He not only loved His neighbour as Himself, but He loved him more than Himself, for He laid down His own life for others. In this, He called upon His disciples to follow Him: to be ready on all occasions to lay down their lives for each other and for enemies, if it would save them from hell (Rom. 5:8-11). This surpassed by far the moral systems of all religions. No system ever prescribed anything so pure and unselfish.
Christ explained to them, that they have been ambitious, envious, and at strife for supremacy. This cannot be. They must love as He loves. By this shall all people know them to be Christians. Disciples of different teachers were known by their habits, or some particular creed or rite; but the Disciples of Christ were to be known by the love they had for one another (1Jn. 3:11-18; 4:7-21).