2:28-32 The promise began to be fulfilled on the day of Pentecost, when the Holy Spirit was poured out, and it was continued in the converting grace and miraculous gifts conferred on both Jews and Gentiles. The judgments of God upon a sinful world, only go before the judgment of the world in the last day. Calling on God supposes knowledge of him, faith in him, desire toward him, dependence on him, and, as evidence of the sincerity of all this, conscientious obedience to him. Those only shall be delivered in the great day, who are now effectually called from sin to God, from self to Christ, from things below to things above.
32. call on … name of … Lord—Hebrew, Jehovah. Applied to Jesus in Ro 10:13 (compare Ac 9:14; 1Co 1:2). Therefore, Jesus is Jehovah; and the phrase means, "Call on Messiah in His divine attributes."
shall be delivered—as the Christians were, just before Jerusalem's destruction, by retiring to Pella, warned by the Saviour (Mt 24:16); a type of the spiritual deliverance of all believers, and of the last deliverance of the elect "remnant" of Israel from the final assault of Antichrist. "In Zion and Jerusalem" the Saviour first appeared; and there again shall He appear as the Deliverer (Zec 14:1-5).
as the Lord hath said—Joel herein refers, not to the other prophets, but to his own words preceding.
call—metaphor from an invitation to a feast, which is an act of gratuitous kindness (Lu 14:16). So the remnant called and saved is according to the election of grace, not for man's merits, power, or efforts (Ro 11:5).