So we see that they could not enter in because of unbelief. (Hebrews 3:19 KJV)
I will commit my way unto the Lord, trust in Him, and he shall surely bring it to pass. I will believe God’s report, and the arm of the Lord shall be revealed unto me, and I will believe on his name and He will give me power to become a son of God.
“Even as Abraham believed God, and it was accounted to him for righteousness. Know ye therefore that they which are of faith, the same are the children of Abraham. And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed. So then they which be of faith are blessed with faithful Abraham.”
Galatians 3:6-9 KJV