A.T. Robertson Commentary Acts 2:21

"And it shall be, that whosoever shall call on the name of the Lord shall be saved." — Acts 2:21 (ASV)

Shall call on (επικαλεσητα). First aorist middle subjunctive of επικαλεω, common verb, to call to, middle voice for oneself in need. Indefinite relative clause with εαν and so subjunctive, punctiliar idea, in any single case, and so aorist.