Rom 4:17 – ( As it is written, I have made thee a father of many Nations , before him whom he believed , even God, who quickeneth the dead, and calleth those things which he not as though they were. 4:19 – And being not weak in Faith , he considered not his own body now dead, when He was about an hundred years old, neither yet the deadness of Sarah’s womb: 4:20 – He staggered not at the promise of God through unbelief but was strong in Faith , giving Glory to God.

God’s kind of Faith call those things which be not as if they are. So Faith has nothing to do with the physical for Abraham, so he did not consider the present state of his body but rather believed God, instead of complaining.