And he received circumcision as a sign, a seal of the righteousness that he had by faith while he was still uncircumcised. So then, he is the father of all who believe but have not been circumcised, in order that righteousness might be credited to them.
NIV
He received the mark of circumcision as a token or an evidence [and] seal of the righteousness which he had by faith while he was still uncircumcised--[faith] so that he was to be made the father of all who [truly] believe, though without circumcision, and who thus have righteousness (right standing with God) imputed to them and credited to their account
AMP
And he received the sign of circumcision, a seal of the righteousness of the faith which he had yet being uncircumcised: that he might be the father of all them that believe, though they be not circumcised; that righteousness might be imputed unto them also:
KJV
Against all hope, Abraham in hope believed and so became the father of many nations, just as it had been said to him, "So shall your offspring be."
NIV
[For Abraham, human reason for] hope being gone, hoped in faith that he should become the father of many nations, as he had been promised, So [numberless] shall your descendants be. [Gen. 15:5.]AMP
Who against hope believed in hope, that he might become the father of many nations, according to that which was spoken, So shall thy seed be.
KJV