This is the great purpose for which God sent His Son into the world (cf. on John 3:16; 10:10). In his Gospel, John usually employs the phrase “to have life” rather than the verb “to live,” as here, but the variation in phraseology involves no difference in meaning.

 God’s Son did not attempt to save man from a distance. He came into man’s own environment, though still retaining His connection with heaven (see on John 1:9, 10). He was in the world, but He was never “of the world,” just as we must not be “of the world” (John 17:14; 1 John 4:4, 5).

 Gr. monogenēs (see on John 1:14). Monogenēs as applied to the Son occurs only in John’s writings, and thus supports the view that the Gospel and the epistle have a common authorship (see p. 623).

 Literally, “hath sent.” The form of the Greek verb presents the act of sending as in the past, but with its effects remaining. Significantly, the results of the sending are permanent for Christ—He remains one of us (see on John 1:14; see Vol. V, pp. 917, 918; 1126-1131). The sending was not that of a father ordering a son to undertake a difficult mission, for Christ’s sacrifice was voluntary (see on John 10:17, 18; see DA 22, 23). He gladly undertook to become man and to die for sinners (see Ps. 40:8; Phil. 2:5-8; Rev. 13:8; PP 63; DA 23).

Rather, “in us,” or “among us” (RSV).

That is, God’s love, as the context shows.

 Compare on ch. 1:2, where John tells us that eternal life was manifested in Christ, and on ch. 3:5, where the same verb is used for the incarnation.

The phrase refers to what follows, not to what goes before.

 All life is derived from Christ (see on John 1:3; Col. 1:16, 17; Heb. 1:3). Nothing has life apart from Christ. But, in a special sense, the Christian lives “through him,” for the only life that has permanent value, eternal life, is gained only through Jesus (cf. on John 10:10; 1 John 5:11, 12).