Berean Study Bible
When God made His promise to Abraham, since He had no one greater to swear by, He swore by Himself,

King James Bible
For when God made promise to Abraham, because he could swear by no greater, he sware by himself,

American Standard Version
For when God made promise to Abraham, since he could swear by none greater, he sware by himself,

Darby Bible Translation
For God, having promised to Abraham, since he had no greater to swear by, swore by himself,

Douay-Rheims Bible
For God making promise to Abraham, because he had no one greater by whom he might swear, swore by himself,

English Revised Version
For when God made promise to Abraham, since he could swear by none greater, he sware by himself,

Young's Literal Translation
For to Abraham God, having made promise, seeing He was able to swear by no greater, did swear by Himself,