And it shall come to pass, that whosoever shall call on the name of the LORD shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the LORD hath said, and in the remnant whom the LORD shall call. Whosoever shall call on the name of the Lord - כל אשר יקרא בשם יהוה col asher yikra beshem Yehovah, "All who shall invoke in the name of Jehovah." That Christ is the Jehovah here mentioned appears plain from Romans 10:15, where the reader had better consult the notes. "This refers," says Bp. Newcome, "to the safety of the Christians during the Jewish and the Roman war." It may: but it has a much more extensive meaning, as the use of it by St. Paul, as above, evidently shows. Every man who invokes Jehovah for mercy and salvation by or in the name, Jesus - that very name given under heaven among men for this purpose - shall be saved. Nor is there salvation in any other; and those who reject him had better lay these things to heart before it be too late.
For in Mount Zion and in Jerusalem - Our blessed Lord first began to preach the Gospel in Mount Zion, in the temple, and throughout Jerusalem. There he formed his Church, and thence he sent his apostles and evangelists to every part of the globe: "Go ye into all the world, and preach the Gospel to every creature." Of the Jews there was but a remnant, a very small number, that received the doctrine of the Gospel, here termed the remnant that the Lord should call; קרא kore, whom he calleth. Many were called who would not obey: but those who obeyed the call were saved; and still he delivers those who call upon him; and he is still calling on men to come to him that they may be saved.
Commentary on the Bible, by Adam Clarke [1831].