"Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned--" - Romans 5:12
"For if, because of one man's trespass, death reigned through that one
man, much more will those who receive the abundance of grace and the
free gift of righteousness reign in life through the one man Jesus
Christ. Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men. For as by the one man's disobedience the many were made sinners, so by the one man's obedience the many will be made righteous." - Romans 5:17-19
Adam had sinned. In the eyes of Adonai, his sin made it so that every man that came after him would be a defiled creature the same way Adam was.
A single action of a single man had a consequence on all man kind. Through Adam's disobedience we are all disobedient.
Take Avraham for instance. He believed Adonai and that was considered righteousness in the eyes of Adonai. A single action of one man made it so that Adonai chose to bless and protect all those that were born from the seed of Avraham.
It is not fair that we should all be counted as sinners because of one man. It is not fair that all Jews should be blessed by the obedience of one man and most certainly it is not fair that by the obedience of one man many are righteous. It is not fair that I get the same reward as the One that deserves reward, but that is how Adonai does things.
If I can believe that I am a sinner because of Adam's sin, then i must also believe that I am righteous because of Yeshua's obedience. Even if I don't feel righteous and I find it much easier to believe and accept that I am a sinner, I must understand Adonai's way of doing things and believe that Yeshua's action was at least as powerful as Adam's.
If by sinning, Adam was able to influence my condition 6000 years later, then I know for a fact that Yeshua and His obedience can make me righteous 2000 years later.
Yes, I was not the one that broke Adonai's commandment, I was not the one that ate from the tree, still I feel the consequence of that transgression as if I was the one who did it. The same way, I was not the one that obeyed The Father by dying on the cross, still... I live the consequence of Yeshua's obedience as if I had been obedient.
"... so that, as sin reigned in death, grace also might reign through
righteousness leading to eternal life through Jesus Christ our Lord" - Romans 5:21
Bat Melech בת מלך