Romans 4:18

Romans 4:18 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.

Earlier in chapter four of Romans Abraham is used to explain how someone is justified today in the Dispensation of Grace. In verse five, a man is justified by faith apart  from works or without works. Abraham's faith was accounted to him for righteousness. Righteousness was counted to his account, because he believed. And in verses 9-12, it explains that Abraham's faith was accounted for righteousness while he was still uncircumcised.

The word "against" in verse 18 means "beyond." Humanly speaking, both Abraham and Sarah had no hope of ever reproducing because they were old. It was beyond hope. But God, who gives life to the dead and calls those things that don't exist as though they did exist (verse 17) gave them that hope. And hope, according to the Bible, means an earnest expectation (Phil. 1:20). Abraham could expect what God told him would happen. Where there seemed to be no hope from man's perspective, from God's perspective there was hope. And Abraham simply believed/trusted God. And because of that faith, righteousness was accounted to him. It wasn't by works or by circumcision. It was by faith alone.

We too are justified by faith today!

Romans 5:1 Therefore being justified by faith, we have peace with God through our Lord Jesus Christ:

God has already reconciled the world unto Himself by not imputing our trespasses unto ourselves, but instead He imputed (counted) our sin on the Lord Jesus Christ Himself. Christ, who knew no sin, was made sin for us (2 Cor. 5:21). God is no longer counting your sin against you. All of your sin is paid for! All you have to do to receive eternal life, or in other words, be made the righteousness of God in Christ is believe! Take God at His Word. He said he has already paid for your sins. He said that he is no longer charging you with your sin. All you have to do is believe! Believe that Christ died for your sins, was buried, and rose again the third day! (1 Cor. 15:1-4) By believing what Christ has already done on your behalf you are then made the righteousness of God in Him.