The clause the world passes away, and the lust of it expresses the second reason for the exhortation given in verse 15a. The verb has durative aspect, referring to a continuing process that will be, but is not yet, completed. It may also be rendered ‘is ending,’ ‘is coming to its end,’ ‘is on its way to perish,’ ‘will not exist much longer,’ ‘is fading/disappearing.’

The phrase the lust of it briefly sums up the three phrases of verse 16. The pronoun may refer to the goal, that is, to what men desire, which leads to a rendering like “everything in it that men desire” (Good News Translation). Or it may refer to the agent; hence, ‘what it (or the world) lusts after’; compare also ‘the desires it (or the world) arouses.’ The latter interpretation agrees with that of the comparable constructions in verse 16.

He who does the will of God abides for ever is in strong contrast to the preceding clause. Whereas the evil world is on the way to its end and has no permanence, those who do God’s will are without end and share in the permanent life of God.

“To do the will of” is a Hebraistic expression often found in the New Testament. It may be rendered here ‘to act according to God’s will,’ ‘to do what God demands,’ ‘to do what God tells one to do.’ Some idiomatic renderings are ‘to follow God’s heart,’ ‘to do the thing-loved of god.’ For comparable Hebraisms with “to do,” see the note on “do not live according to the truth” in 1.6.

In some receptor languages the will is identified with various parts of the body. This may result in rendering the will of God by such expressions as ‘the stomach of God,’ ‘what comes from God’s abdomen,’ or, laying a close connection between the voice and the will, ‘the throat/larynx of God.’

“To abide,” that is, to be-and-remain; in this context, ‘to stay,’ or ‘to live.’ Compare the note on “to abide in him” in 1 John 2.6. For for ever, see “eternal” in 1.2.

Quoted with permission from Haas, C., de Jonge, M. and Swellengrebel, J.L. A Handbook on The First Letter of John. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .