Saved By Faith. Genesis 15:6 NLT

We are saved by faith, not by works.

"When Abram put his trust in God, specifically in God’s promise to him (descendants leading to the Messiah), God credited this belief to Abram’s account as righteousness.

There are essentially two types of righteousness: righteousness we accomplish by our own efforts, and righteousness accounted to us by the work of God when we believe.

Since none of us can be good enough to accomplish perfect righteousness, we must have God’s righteousness accounted to us by doing just what Abram did: he believed in the Lord.

God’s accounting is not pretending. God does not account to us a pretended righteousness, but a real one in Jesus Christ. " David Guzik

For what does the Scripture say? “Abraham believed God, and it was accounted to him for righteousness.” ( Romans 4:1-3)

It's not by works:

Does this blessedness then come upon the circumcised only, or upon the uncircumcised also? For we say that faith was accounted to Abraham for righteousness. How then was it accounted? While he was circumcised, or uncircumcised? Not while circumcised, but while uncircumcised. ( Romans 4:9-10)

It's not by believing God exists, but by believing God's word:

And not being weak in faith, he did not consider his own body, already dead (since he was about a hundred years old), and the deadness of Sarah’s womb. He did not waver at the promise of God through unbelief, but was strengthened in faith, giving glory to God, and being fully convinced that what He had promised He was also able to perform. And therefore “it was accounted to him for righteousness.” Now it was not written for his sake alone that it was imputed to him, but also for us. It shall be imputed to us who believe in Him who raised up Jesus our Lord from the dead ( Romans 4:19-24).

Believing God and His promises:

Therefore He who supplies the Spirit to you and works miracles among you, does He do it by the works of the law, or by the hearing of faith?; just as Abraham “believed God, and it was accounted to him for righteousness.” Therefore know that only those who are of faith are sons of Abraham.( Galatians 3:5-7)

Genesis 15:6 NLT

6 And Abram believed the LORD, and the LORD counted him as righteous because of his faith.

Blessings, Cecilia

https://www.thoughtco.com/what-is-righteousness-700695