Romans 4:20
ESV
No unbelief made him waver concerning the promise of God, but he grew strong in his faith as he gave glory to God,
NIV
Yet he did not waver through unbelief regarding the promise of God, but was strengthened in his faith and gave glory to God,
NASB
yet, with respect to the promise of God, he did not waver in unbelief but grew strong in faith, giving glory to God,
CSB
He did not waver in unbelief at God’s promise but was strengthened in his faith and gave glory to God,
NLT
Abraham never wavered in believing God’s promise. In fact, his faith grew stronger, and in this he brought glory to God.
KJV
He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God;
NKJV
He did not waver at the promise of God through unbelief, but was strengthened in faith, giving glory to God,
What does Romans 4:20 mean?
Abraham waited many, many years for God to keep His promise to give Abraham and Sarah a son. That promise wasn't given until Abraham was more than 75 years old, and wasn't fulfilled until Abraham was 100, some 25 years later! Paul wrote in the previous verse that Abraham's faith did not weaken. He held fast to his faith, even long after the hope of having a natural-born son became impossible according to human experience. Now, Paul writes that Abraham experienced no unbelief. He didn't waver in trusting God. Just the opposite: He grew stronger in his faith and continued to give glory to God.Abraham's faith was undeniably remarkable. He was far from a perfect man. Abraham sinned, as all do. But He believed that the God who spoke to Him would do exactly what He promised even as year after year passed without that promise being fulfilled.
Romans 4:13–25 continues to focus on the faith of Abraham. God made promises to Abraham and his descendants, promises which Abraham believed. Those promises can't be received by keeping the law, but only by faith. God promised Abraham a son with Sarah, and Abraham continued to believe that promise would be kept even as it became less and less likely in human terms. We, too, can be counted as righteous by faith in Jesus' death for our sins and God's resurrection of Him for our justification.
Romans 4 is all about the faith of Abraham. God declared Abraham righteous because of his faith, not because of his works. A declaration of righteousness was God's gift, not a payment. This righteousness is available to everyone, circumcised or not. God declared Abraham righteous many years before he was circumcised, making him the spiritual father of all who believe, whether circumcised or not, whether Jew or Gentile. God's promises to Abraham and his offspring can't be received by keeping the law, only by faith. Abraham's faith in God's promise of a son with Sarah did not waver even as he grew older. God will declare us righteous, as well, if by faith we believe in the God who delivered Jesus to die for our sins and raised Him back to life for our justification.