Berean Standard Bible (BSB)
When God made His promise to Abraham, since He had no one greater to swear by, He swore by Himself,
World English Bible (WEB)
For when God made a promise to Abraham, since he could swear by none greater, he swore by himself,
Strong's King James
For{G1063} when God{G2316} made promise{G1861}{(G5666)} to Abraham{G11}, because{G1893} he could{G2192}{(G5707)} swear{G3660}{(G5658)} by{G2596} no{G3762} greater{G3187}, he sware{G3660}{(G5656)} by{G2596} himself{G1438},
The F.O.G *
(13) For יהוה YAHWEH made the vow to Avraham (Father of Multitude) and since He could vow an oath by nothing greater, He vowed an oath to Himself. Surely saying,
The F.O.G Message *
Young's Literal Translation
For to Abraham God, having made promise, seeing He was able to swear by no greater, did swear by Himself,