Literally, were begotten. The phrase γεννηθήναι ἐκ τοῦ Θεοῦ, to be born or begotten of God, occurs only here in the Gospel, and several times in the First Epistle. It is peculiar to John.
There is a progress of thought in the three following clauses, describing the proper origin of a believer's new life. Children of God are begotten, not of blood, nor of the will of the flesh, nor of the will of man. “The new birth is not brought about by descent, by desire, or by human power” (Westcott).
Of blood (ἐξ αἱμάτων)
Literally, of bloods. The plural is variously explained: by some as indicating the duality of the sexes, by others of the multiplicity of ancestors. The best explanation seems to be afforded by a similar use of the plural in Plato, ἔτι ἐν γάλαξι τρεφόμενοι, “while still nourished by milks” (“Laws,” 887). The fluids, blood or milk being represented as the sum-total of all their parts. Compare τὰ ὕδατα, the waters.