Romans 4:11-17 And he received the sign of circumcision, a seal of the righteousness of the faith/trust which he had yet being uncircumcised: that he might be the father of all them that believe, though they be not circumcised; that righteousness might be imputed to them also: And the father of circumcision to them who are not of the circumcision only, but who also walk in the steps of that faith of our father Avraham, which he had being yet uncircumcised. For the promise, that he should be the heir of the world, was not to Avraham, or to his seed, through the law, but through the righteousness of faith. For if they which are of the law(instruction) be heirs, faith/trust is made void, and the promise made of none effect: Because the law works wrath: for where no law is, there is no transgression. Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Avraham; who is the father of us all, (As it is written, I have made thee a father of many nations,) before him whom he believed, even G-d, who quickens the dead, and calls those things which be not as though they were.
The Avrahamic Covenant still stands
Tehillim (Psalms) 105:8-10 He has remembered His covenant forever, the word which He commanded to a thousand generations, The covenant which He made with Avraham, And His oath to Isaac. Then He confirmed it to Jacob for a statute, To Israel as an everlasting covenant,
(See also Gen. 12, Joel 3)
The land of Canaan still belongs to Israel. B'rit Hadashah does not replace those promises. (That teaching is what is considered replacement theology. It is a false teaching.)
The Mosaic Law never promised eternal redemption. The Mosaic covenant governs Israel. And the Mosaic Law tells the ungodly that they are sinners. The spirit of the law is still a good guideline for believers.
Wilmington explains some terms:
"Believed"
"1. This does not mean that Avram was the first man to believe in G-d, but rather that his faith is to be a pattern for all future believers. (See Romans 4; Gal. 3:6; Heb. 11:8-10,17,19)"
Galatians 3:6 Even so Avraham believed G-d, and it was reckoned to him as righteousness.
"2. It does not say Avram pleased G-d or appeased Him, but that he believed in G-d."
"Counted" " In the New Testament (Brit Hadashah) "imputed." To impute means to add to one's account. There are three main imputations in the Bible."
"1. The imputation of Adam's sin upon the human race
(Rom. 3:23; 5:12)"
Romans 5:12 Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned--
"2. The imputation of the race's sin upon Messiah (Christ)
Isaiah 53:5-6 But He was pierced through for our transgressions, He was crushed for our iniquities; the chastening for our well-being fell upon Him, And by His scourging we are healed. All of us like sheep have gone astray, each of us has turned to his own way; But the L-RD has caused the iniquity of us all To fall on Him.
(See also Heb. 2:9; 2 Cor. 5:14-21; 1 Pet. 2:24)."
"3. The imputation of G-d's righteousness upon the believing sinner
James 2:23 and the Scripture was fulfilled which says, "And Avraham believed G-d, and it was reckoned to him as righteousness," and he was called the friend of G-d.
(See also Phil. 3:9; Rom. 4:6, 8, 11, 22, 23, 24)"
"Righteousness" This word, simply defined, means "right clothing." The Bible teaches that all sinners are naked before G-d (Gen. 3:10; Heb. 4:13; Rev. 3:17) Some realize this and attempt to make their own set of spiritual clothes, but G-d looks upon such clothes as filthy rags (Isaiah 64:6) Therefore whenever a sinner realizes his nakedness and calls on the mercy of G-d, he gets a new suit of clothes.
(See 2 Cor. 6:7; Eph. 6:14; Rev. 19:7, 8.)"
(Wilmington, H. L. Wilmington's Guide to the Bible. Wheaton, Illinois: Tyndale House Publishers, Inc., 1981, Pg. 39.)
Adam and Eve tried to cloth themselves in "Right Clothing" (righteousness). They used fig leaves. This was unacceptable to G-d because He requires a blood sacrifice to atone for sin. He clothed them in animal skins. This implies that there was a blood sacrifice made to Him first.
Romans 4:18-25 He was past hope yet in hope he trusted, that he might become the father of many nations; according to that which was spoken, So will your seed be. And being not weak in faith/trust, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sara's womb: He staggered not at the promise of G-d (HaShem) through unbelief; but was strong in faith/trust, giving glory to G-d; And being fully persuaded that, what he had promised, he was able also to perform. And therefore it was imputed to him for righteousness. Now it was not written for his sake alone, that it was imputed to him; but for us also, to whom it will be imputed, if we believe on him that raised up Yeshua our L-rd from the dead; who was delivered for our offences, and was raised again for our justification.
All who trust in Yeshua, believing that He died for our sins and rose again, will have our sins forgiven. We will be counted righteous just like Avraham was.