ISB ~ Matthew 16 v16

Son of the living God:The confession is double-sided: (1) Peter proclaims the mystery of Christ’s divinity as the head and spokesman of the Church (cf. 11:25-27; 14:33). (2) Peter sees Jesus as the awaited Messiah-king of Israel (26:63; Jn 1:49). The close relationship between the titles Christ and Son reflects OT traditions, where Israel’s kings enjoyed unique relationships with God as his sons (2 Sam 7:14; Ps 2:7; 89:27; CCC 436, 439, 442).

See word study:Christ at Mk 14.