Romans 3:29 affirms God is God of both Jews and Gentiles—directly supporting the 'whosoever' basis of salvation in Romans 10:13.

Romans 4:9 questions whether salvation is only for Jews, echoing the 'everyone' in 10:13 — both affirm God's salvation is for all who believe.

Joel 2:32 is the exact OT verse quoted here: 'everyone who calls on the name of the Lord will be saved.'

Acts 2:21 also quotes Joel 2:32 at Pentecost, applying the same salvation promise to all who call on the Lord.

Psalm 86:5 echoes the same promise: the Lord is ready to forgive and abounds in mercy toward all who call on Him.

Acts 11:18 states that God granted repentance unto life to Gentiles—echoing the universal scope of salvation in Romans 10:13.

Psalm 91:15 assures that when one calls, God answers and delivers—though deliverance here is more temporal than eternal salvation.

1 Thessalonians 2:16 shows Jewish opposition to preaching to Gentiles — the very people Paul says in 10:13 can call on the Lord and be saved.