Rom 3:22-24
This righteousness from God comes through faith in Jesus Christ to all who believe. There is no difference, for all have sinned and fall short of the glory of God, and are justified freely by his grace through the redemption that came by Christ Jesus.
No question here that ALL have sinned. Also, no question that we are justified freely by His grace!

Rom 4:3
What does the Scripture say? "Abraham believed God, and it was credited to him as righteousness."
Rom 4:10
Under what circumstances was it credited? Was it after he was circumcised, or before? It was not after, but before!

Interesting that the “son of promise”, Isaac, was conceived after Abraham’s circumcision. Ishmael was conceived before the circumcision.

Abraham’s faith didn’t waver concerning the promise of an offspring. Sarah, on the other hand, felt that she should offer her handmaiden, Hagar to Abraham in order to fulfill the promise, since she was too old to bear children (or so she thought).
Rom 4:20-21
Yet he did not waver through unbelief regarding the promise of God, but was strengthened in his faith and gave glory to God, being fully persuaded that God had power to do what he had promised.
Do we as Christians waver through unbelief regarding the promises of God or are we strengthened in our faith and give glory to God? Are we fully persuaded that God has power to do what he has promised or are we like Sarah and try to “help God out”?

Rom 8:15
For you did not receive a spirit that makes you a slave again to fear, but you received the Spirit of sonship. And by him we cry, "Abba, Father."

Just before Jesus was arrested, He prayed this prayer in the Garden.
Mark 14:36
"Abba, Father," he said, "everything is possible for you. Take this cup from me. Yet not what I will, but what you will."
Abba is a term of endearment, something like our English word, Daddy. As we have watched Jesus repeatedly speak of the Father the closer He gets to the crucifixion, it seems as if He hungers for the presence of Abba, Daddy. Do we as Christians hunger to be in the presence of Abba, Daddy?

Rom 8:37-39
No, in all these things we are more than conquerors through him who loved us. For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.
Paul makes it pretty clear that nothing can separate us from the love of God in Christ Jesus!