ὀϊσάμην

From LSJ

Χριστὸς ἀνέστη ἐκ νεκρῶν, θανάτῳ θάνατον πατήσας, καὶ τοῖς ἐν τοῖς μνήμασι, ζωὴν χαρισάμενος → Christ is risen from the dead, trampling down death by death, and upon those in the tombs bestowing life

Source

Russian (Dvoretsky)

ὀϊσάμην: эп. aor. к οἴομαι.