The "Lord" of Joel 2:32 is the same as the "Lord Jesus Christ." Peter also appealed to Joel 2:32 in his Pentecost sermon for the same reason Paul did here ( Acts 2:21). Both apostles wanted to show that the door of salvation is open to everyone. When the elect call on God they are responding to His calling of them ( Romans 8:28-30). The only prayer of an unbeliever that God has promised to answer is this prayer for salvation, though He sometimes graciously answers other prayers that they pray. [source][source][source]
Possibly Paul had a more restricted concept of salvation in mind in this verse. [source][source][source]
"This verse ( Romans 10:13) is a quotation from Joel 2:32 and refers to the physical deliverance from the future day of wrath upon the earth and the restoration of the Jews to Palestine and not deliverance from hell." [1][source]
Context Summary
Romans 10:11-21 - Needing Messengers Of Good Tidings
The Chosen People chafed, not only at the freeness of God's justifying grace, but because there was no difference made, so far as salvation was concerned, between them and the Gentiles. Surely there ought to be a special doorway for them into eternal life, apart from that trodden by the feet of the ordinary heathen world! Were they not the children of Abraham, the friend of God? Here the Apostle was compelled to withstand them. No, said he, it cannot be! There is no difference between Jew and Greek. All have sinned, and the same Lord is over all, rich to those who call upon Him, of whatever nationality.
The guests for whom the marriage feast was prepared refused to come, and therefore it was decreed that the servants of the great King should preach the gospel to every creature, and scour the highways and byways of the world for guests. The remainder of the chapter, Romans 10:14, etc., therefore vindicates the Apostle in his determination to preach the gospel beyond the limits of his own people; and in doing so, he was acting upon the old words of Deuteronomy 32:21. God would provoke their jealousy by a no-people, as they had provoked His by no-gods, Romans 10:19. [source]
Chapter Summary: Romans 10
1The difference between the righteousness of the law, and that of faith; 11all who believe, both Jew and Gentile, shall not be shamed; 18and that the Gentiles shall receive the word and believe 19Israel was not ignorant of these things
Romans 10:14How then shall they call? [πως ουν επικαλεσωνται] Deliberative subjunctive (first aorist middle) of επικαλεομαι epikaleomai (see Romans 10:12,Romans 10:13). The antecedent of εις ον eis hon (in whom) is not expressed. [source]
Greek Commentary for Romans 10:13
Paul here quotes Joel 3:5 ( Joel 2:32 , lxx). [source]
Reverse Greek Commentary Search for Romans 10:13
Deliberative subjunctive (first aorist middle) of επικαλεομαι epikaleomai (see Romans 10:12, Romans 10:13). The antecedent of εις ον eis hon (in whom) is not expressed. [source]
Rev., better, witness. A common classical idiom. Compare Plato: “Next will follow the choir of young men under the age of thirty, who will call upon the god Paean to testify to the truth of these words” (“Laws,” 664). Homer: “For the gods will be the best witnesses” (“Iliad,” xxii., 254). Compare Romans 1:9; Galatians 1:20; Philemon 1:8; 1 Thessalonians 2:5, 1 Thessalonians 2:10; Genesis 31:50, Sept. This particular form of expression occurs nowhere else in the New Testament. The verb is often translated appeal, as Acts 25:11, Acts 25:12. Also to call upon, in the sense of supplication, Romans 10:12, Romans 10:13, Romans 10:14; 1 Corinthians 1:2. [source]
A Pauline phrase, only here in Pastorals. See Romans 10:12, Romans 10:13, Romans 10:14; 1 Corinthians 1:2. See also Acts 2:21; Acts 9:14; Acts 22:16. [source]