2 “Now Jesus knew,” as the evangelist proceeds to say, “that they were desirous to ask Him, and said unto them, You inquire among yourselves of that I said, A little while, and you shall not see me: and again a little while, and you shall see me. Verily verily, I say unto you, That you shall weep and lament, but the world shall rejoice; and you shall be sorrowful, but your sorrow shall be turned into joy:” which may be understood in this way, that the disciples were thrown into sorrow over the death of the Lord, and straightway were filled with joy at His resurrection; but the world, whereby are signified the enemies that slew Christ, were, of course, in a state of rapture over the murder of Christ, at the very time when the disciples were filled with sorrow. For by the name of the world the wickedness of this world may be understood; in other words, those who are the friends of this world. As the Apostle James says in his epistle, “Whosoever will be a friend of this world, has become the enemy of God;” for the effect of that enmity to God was, that not even His Only-begotten was spared.
Source: Tractates on the Gospel of John (New Advent)