am - Not merely was I in times past, but I still am the least worthy of so high an office (compare 1Ti 1:15, end).
least of all saints - not merely “of all apostles” (1Co 15:9, 1Co 15:10).
is - Greek, “has been given.”
among - omitted in the oldest manuscripts Translate, “to announce to the Gentiles the glad tidings of the unsearchable (Job 5:9) riches,” namely, of Christ’s grace (Eph 1:7; Eph 2:7). Rom 11:33, “unsearchable” as a mine inexhaustible, whose treasures can never be fully explored (Eph 3:18, Eph 3:19).