ل َمّا قَطَعَ اللهُ وَعداً لإبراهِيْمَ أقْسَمَ بِنَفسِهِ، إذْ لَيْسَ هُناكَ مَنْ هُوَ أعظَمُ مِنْهُ فَيُقسِمَ بِهِ.
When God made a promise to Abraham, He made that promise in His own name because no one was greater.