On Greek, see on Act 6:1. Greeks here equivalent to Gentiles.
Lord (κύριος)
See on Mat 21:3. The reference is disputed: some Christ, others God. Probably Christ. See Rom 10:9, and compare Act 10:36. The hearing which is necessary to believing comes through the word of Christ (Rom 10:17, where the reading is Christ instead of God).
That call upon (ἐπικαλουμένους)
See on appeal, Act 25:11; see on Jam 2:7. That invoke Him as, Lord: recalling Rom 10:9, Rom 10:10. Compare Joe 2:32.