Hebrews 6:17 New International Version (NIV)
Because God wanted to make the unchanging nature of his purpose very clear to the heirs of what was promised, he confirmed it with an oath.
Hebrews 6:13-18 The Message (MSG)
When God made his promise to Abraham, he backed it all the way, putting his own reputation on the line. He said, “I promise that I’ll bless you with everything I have—bless and bless and bless!” Abraham stuck it out and got everything that had been promised to him. When people make promises, they guarantee them by appeal to some authority above them so that if there is any question that they’ll make good on the promise, the authority will back them up. When God wanted to guarantee his promises, he gave his word, a rock-solid guarantee—God can’t break his word. And because his word cannot change, the promise is likewise unchangeable.
Hebrews 6:17 New American Standard Bible - NASB 1995 (NASB1995)
In the same way God, desiring even more to show to the heirs of the promise the unchangeableness of His purpose, interposed with an oath
Hebrews 6:17 New Living Translation (NLT)
God also bound himself with an oath, so that those who received the promise could be perfectly sure that he would never change his mind.
Hebrews 6:17 King James Version (KJV)
Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath
Hebrews 6:17 New Century Version (NCV)
God wanted to prove that his promise was true to those who would get what he promised. And he wanted them to understand clearly that his purposes never change, so he made an oath.
Hebrews 6:17 American Standard Version (ASV)
Wherein God, being minded to show more abundantly unto the heirs of the promise the immutability of his counsel, interposed with an oath
Hebrews 6:17 New King James Version (NKJV)
Thus God, determining to show more abundantly to the heirs of promise the immutability of His counsel, confirmed it by an oath
Hebrews 6:17 Amplified Bible (AMP)
In the same way God, in His desire to show to the heirs of the promise the unchangeable nature of His purpose, intervened and guaranteed it with an oath
Hebrews 6:17 The Passion Translation (TPT)
So in the same way, God wanted to end all doubt and confirm it even more forcefully to those who would inherit his promises. His purpose was unchangeable, so God added his vow to the promise.