שָׁבַע shâbaʻ (H7650)

to seven oneself, i.e. swear (as if by repeating a declaration seven times)

1) to swear, adjure 1a) (Qal) sworn (participle) 1b) (Niphal) 1b1) to swear, take an oath 1b2) to swear (of Jehovah by Himself) 1b3) to curse 1c) (Hiphil) 1c1) to cause to take an oath 1c2) to adjure

a primitive root; properly to be complete, but used only as a denominative from שֶׁבַע (H7651);