Know ye that our brother Timothy is set at liberty - Or, is sent away. So it is rendered by Prof. Stuart and others. On the meaning of this, and its importance in determining who was the author of the Epistle, see the Introduction section 3, (5) 4, and Prof. Stuart’s Introduction, section 19. This is a strong circumstance showing that Paul was the author of the Epistle, for from the first acquaintance of Timothy with Paul he is represented as his constant companion, and spoken of as a brother; 2 Corinthians 1:1 note; Philippians 1:1 note; Colossians 1:1 note; Philippians 1 note. There is no other one of the apostles who would so naturally have used this term respecting Timothy, and this kind mention is made of him here because he was so dear to the heart of the writer, and because he felt that they to whom he wrote would also feel an interest in his circumstances. As to the meaning of the word rendered “set at liberty” - ἀπολελυμένον apolelumenon - there has been much difference of opinion whether it means “set at liberty from confinement,” or, “sent away on some message to some other place.” That the latter is the meaning of the expression appears probable from these considerations.
(1) The connection seems to demand it. The writer speaks of him as if he were now away, and as if he hoped that he might soon return. “With whom, if he come shortly, I will see you.” This is language which would be used rather of one who had been sent on some embassy than of one who was just released from prison. At all events, he was at this time away, and there was some expectation that he might soon return. But on the supposition that the expression relates to release from imprisonment, there would be an entire incongruity in the language. It is not, as we should then suppose, “our brother Timothy is now released from prison, and therefore I will come soon with him and see you;” but, “our brother Timothy is now sent away, and if he return soon I will come with him to you.”
(2) In Philippians 2:19, Philippians 2:23, Paul, then a prisoner at Rome, speaks of the hope which he entertained that he would be able to send Timothy to them as soon as he should know how it would go with him. He designed to retain him until that point was settled, as his presence with him would be important until then, and then to send him to give consolation to the Philippians, and to look into the condition of the church. Now the passage before us agrees well with the supposition that that event had occurred - that Paul had ascertained with sufficient clearness that he would be released, so that he might be permitted yet to visit the Hebrew Christians, that he had sent Timothy to Philippi and was waiting for his return; that as soon as he should return he would be prepared to visit them; and that in the mean time while Timothy was absent, he wrote to them this Epistle.
(3) The supposition agrees well with the meaning of the word used here - ἀπολύω apoluō. It denotes properly, to let loose from: to loosen; to unbind; to release; to let go free; to put away or divorce; to dismiss simply, or let go, or send away; see Matthew 14:15, Matthew 14:22-23; Matthew 15:32, Matthew 15:39; Luke 9:12, et al.; compare Robinson’s Lexicon and Stuart’s Introduction, section 19. The meaning, then, I take to be this, that Timothy was then sent away on some important embassage; that the apostle expected his speedy return; and that then he trusted that he would be able with him to visit those to whom this Epistle was written.