Hebrews 6:16

16 People swear by someone greater than themselves, and the oath confirms what is said and puts an end to all argument.

Read Hebrews 6:16 Using Other Translations

For men verily swear by the greater: and an oath for confirmation is to them an end of all strife.
For people swear by something greater than themselves, and in all their disputes an oath is final for confirmation.
Now when people take an oath, they call on someone greater than themselves to hold them to it. And without any question that oath is binding.