3:16

loved: This is the first occurrence of the Greek verb a·ga·paʹo (“to love”) in the Gospel of John. This Greek verb and the related noun a·gaʹpe (love) are used in his Gospel a total of 44 times​—more often than in the other three Gospels combined. In the Bible, a·ga·paʹo and a·gaʹpe often refer to unselfish love guided, or governed, by principle. This is shown by its use in this verse, since God is spoken of as loving the world, that is, the world of mankind in need of redemption from sin. (Joh 1:29) The noun is used at 1Jo 4:8, where John says “God is love.” Love (a·gaʹpe) is listed first as an aspect of “the fruitage of the spirit” (Ga 5:22), and it is described at length at 1Co 13:4-7. The way the word is used in the Scriptures shows that love often involves more than an emotional response to another person. In many contexts, it is broader in scope; this type of love is often expressed more thoughtfully and deliberately. (Mt 5:44; Eph 5:25) Therefore, the love cultivated by Christians should include a moral sense that takes into account duty, principle, and propriety. However, it is not without feeling, since it often includes warm personal affection. (1Pe 1:22) This is shown in the use of the term in John’s Gospel. When John wrote “the Father loves the Son” (Joh 3:35), he used a form of the word a·ga·paʹo, but when he recorded Jesus’ statement describing this same relationship, he used a form of the Greek verb phi·leʹo (“to have affection”).​—Joh 5:20.

the world: The Greek word koʹsmos is closely linked with mankind in secular Greek literature and particularly so in the Bible. (See study note on Joh 1:10.) In this context, koʹsmos refers to the entire world of redeemable mankind who at Joh 1:29 are described as being guilty of “sin,” that is, sin inherited from Adam.

only-begotten Son: The Greek word mo·no·ge·nesʹ, traditionally rendered “only-begotten,” has been defined as “the only one of its kind; one and only; unique.” In the apostle John’s writings, this term is exclusively used of Jesus. (Joh 1:14; 3:18; 1Jo 4:9; see study note on Joh 1:14.) Although the other spirit creatures produced by God were called sons, Jesus alone is called the “only-begotten Son.” (Ge 6:2, 4; Job 1:6; 2:1; 38:4-7) Jesus, the firstborn Son, was the sole direct creation of his Father, so he was unique, different from all other sons of God. They were created, or begotten, by Jehovah through that firstborn Son. The Greek word mo·no·ge·nesʹ is used in a similar way when Paul says that Isaac was Abraham’s “only-begotten son.” (Heb 11:17) Though Abraham fathered Ishmael by Hagar and several sons by Keturah (Ge 16:15; 25:1, 2; 1Ch 1:28, 32), Isaac was “only-begotten” in a special sense. He was Abraham’s only son by God’s promise as well as the only son of Sarah.​—Ge 17:16-19.

exercising faith in him: Lit., “believing into him.” The Greek verb pi·steuʹo (related to the noun piʹstis, generally rendered “faith”) has the basic meaning “to believe; to have faith,” but it can express different shades of meaning, depending on context and grammatical constructions. The meaning of this term often goes beyond mere belief or recognition that someone exists. (Jas 2:19) It includes the idea of faith and trust that lead to obedient action. At Joh 3:16, the Greek verb pi·steuʹo is used together with the preposition eis, “into.” Regarding this Greek phrase, one scholar noted: “Faith is thought of as an activity, as something men do, i.e. putting faith into someone.” (An Introductory Grammar of New Testament Greek, Paul L. Kaufman, 1982, p. 46) Jesus obviously refers to a life characterized by faith, not just a single act of faith. At Joh 3:36, the similar expression “the one who exercises faith in the Son” is contrasted with “the one who disobeys the Son.” Therefore, in that context, “to exercise faith” includes the idea of demonstrating one’s strong beliefs or faith through obedience.