The Only Begotten
The expression "only begotten" is an interesting phrase, especially as it applies to Jesus.
The meaning of only begotten. "Only begotten" is from the Greek monogenes. This word is used nine times in the Greek New Testament. The word is a compound word, mono, meaning only, and gennesis, meaning birth. "Only begotten" (monogenes) is used five times by John, three by Luke, and once by the writer of Hebrews. Luke used the word to describe the widow's son, "only son of his mother" (Lk. 7: 12, see 8: 42, 9: 38). The writer of Hebrews said Abraham "offered up his only begotten son" (Heb. 11: 17).
Only begotten as applied to Jesus. The scriptures teach that God's people are "sons of God" (Rom. 8: 14). Modernists contend that Jesus was simply another son of God. Not so! Jesus' Sonship was understood as indicative of deity (Jn. 10: 36, 38). Monogenes is used of Jesus' Sonship. Jesus is the "only begotten Son" (I Jn. 4: 9). "Single of its kind," comments Thayer, " used of Christ, denotes the only Son of God or who in the sense in which he himself is the Son of God has no brethren he is of nature or essentially Son of God, and so in a very different sense from that in which men are made by him children of God" (Thayer's Greek-English Lexicon, pgs. 417, 418). Beloved, God's people are adopted "sons of God," Jesus is the only Son of God by nature (cp. Rom. 8: 14-16).
As God's monogenes Jesus enjoyed unique glory (Jn. 1: 14). The only begotten declared God (Jn. 1: 18). Jesus being of the same essential nature as the Father could reveal God as no other could (Jn. 14: 8-11). The only begotten is the ultimate expression of God's love (Jn. 3: 16, I Jn. 4: 9). Moreover, we must believe in the only begotten Son of God (Jn. 3: 18, 16).
Hence, Jesus is uniquely and singularly the Son of God - the only one of his kind. To realize the only begotten Son of God gave his life for you and me is indeed most humbling.