ISB ~ John 3 v16

gave his only-begotten Son:The earthly mission of Jesus is part of the heavenly plan of the Father, who displays the depth of his love through the sacrifice of his Son (Rom 5:8; 1 Jn 3:16; CCC 219). This verse marks a transition from the dialogue between Jesus and Nicodemus (3:1-15) to an extended monologue by either Jesus or the evangelist himself (3:16-21).

eternal life:The expression refers both to the divine quality of new life in Christ as well as its duration. We receive this gift already on earth in the hope that we will possess it irrevocably in heaven (10:10; 1 Jn 5:13).