Epikaleomai appears 30 times in the New Testament as one of the primary words for calling upon God in prayer and for the theological act of 'calling on the Name of the Lord.' It combines epi (upon) + kaleo (to call) to describe invoking someone by name — whether God (Acts 2:21; Romans 10:13) or a higher authority like Caesar (Acts 25:11). It is also used for naming/surname: Simon 'called' Peter (Acts 10:18).
Romans 10:13 — 'Everyone who calls on [epikaleomai] the name of the Lord will be saved' — quotes Joel 2:32 and places this word at the heart of the salvation formula. Acts 2:21 applies the same Joel citation to Pentecost. Paul himself was 'calling on' the Name of Jesus in Damascus (Acts 9:14, 21) — his persecutor's charge became his converts' testimony. Epikaleomai is the word that connects prayer to salvation, petition to identity, and human calling-out to divine response. To 'call on the Name' is to acknowledge one's need, recognize God's sufficiency, and entrust oneself to His character.