The pronouns in this verse are in the third person singular (compare New English Bible “his days”; Jerusalem Bible, Biblia Dios Habla Hoy, Barclay “a man”). But since it is quite certain that the writer is referring here to Christians, or more specifically his own readers, then rendering the third person singular pronoun as second person plural makes this clear (for example, Good News Translation, New American Bible, Phillips).
This verse in the Greek is not an independent sentence, but a dependent clause, connected with the previous verse by a Greek expression of purpose or result (literally “so that” or “in order that”). This verse may therefore be taken either as expressing the result of “ceasing from sin,” an interpretation which seems to be primary in Good News Translation, Die Bibel im heutigen Deutsch, Revised Standard Version, New English Bible, Biblia Dios Habla Hoy, or as the purpose of “arm yourselves.” Taking this latter sense, what the verse is saying is that Christians should be ready to suffer in order that they may live according to God’s will, not according to human desires (compare Barclay “The object of such suffering is to enable a man to live the rest of his earthly life in obedience, not to human passions, but to God’s will”; King James Version, Revised Version “Arm yourselves with the same mind, that ye no longer should live…”).
From now on may be expressed as “from this day” or “beginning now.”
The conjunction then is best interpreted as result and may be equivalent to “therefore” or “as a result of this.”
Controlled by God’s will (literally “in the will of God”) and human desires (literally “desires of men”) once again express an antithesis which is quite prominent in the letter, that is, the contrast between the condition of people before they become Christian and afterwards (compare 1.14, 18; 2.1, 9, 10, 24, 25). Before they became Christian, they are controlled by human desires, an expression which may be neutral, but is here used negatively (compare 1.14 and 2.11); after conversion, they are controlled by God’s will. Some interpreters see a significance in the singular form of God’s will and the plural form of human desires, in that Christians experience an integration and unity in their lives, which is not true for non-Christians, who are attracted by different loyalties.
You must live … controlled by God’s will may be restructured as “you must let yourselves by controlled by God’s will” or “you must let God control your lives” or “you must live your lives in accordance with what God wants for you.”
And not by human desires may be expressed as “and not by what you yourselves want” or “and not by what your hearts desire.”
The rest of your earthly lives is literally “remaining time in the flesh.” “In the flesh” has a different usage here from that in verse 1, referring primarily to human life on earth. Implied in the statement is the idea that life on earth may not be all that long, since the end of the world is expected any moment, a thought which prevails throughout the whole letter (compare 1.5, 7; 4.7).
You must live the rest of your earthly lives may be expressed as “you must live the remaining days of your life on earth” or “as long as you live here on earth, you must….”
Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on The First Letter from Peter. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .