ISB ~ Acts 2 v36

Lord:A messianic title for Jesus used in the preceding citations from Scripture (2:21, 34). It was a royal title used for the kings of Israel (1 Kings 1:37) as well as a divine title used in the Greek OT to translate the name “Yahweh” (CCC 446, 449).

Christ:The anointed Messiah. See word study: Christ at Mk 14.