Rev., rightly, I give. See on Rev 3:8. The sense is broken off there and resumed here.
Of the synagogue (ἐκ τῆς συναγωγῆς)
Certain ones of the synagogue. Most interpreters refer to the Jews. Others explain more generally, of the bowing down of the Church's enemies at her feet. Trench refers to a passage in the Epistle of Ignatius to this Philadelphian church, implying the actual presence in the midst of it of converts from Judaism, who preached the faith which they once persecuted.
Of Satan
See on Rev 2:9.
I will make them to come (ποιήσω αὐτοὺς ἵνα ἥξωσιν)