For what the law could not do since it was weakened by the flesh, God did. He condemned sin in the flesh by sending his own Son in the likeness of sinful flesh as a sin offering, in order that the law’s requirement would be fulfilled in us who do not walk according to the flesh but according to the Spirit.”Romans 8:3-4 CSB https://bible.com/bible/1713/rom.8.4.CSB
We who live in the flesh, that is all of humanity, are and have been since the fall of Adam, incapable of perfectly living as God requires. Why is it so hard for so many to accept that a perfect God requires perfect obedience to His commands? Isn’t it His perfection and His requirement for perfection that makes Him Holy? Since humanity cannot live according to His law in perfect adherence to that law God came Himself to live perfectly the law as a man. Having lived the law perfectly He could sacrifice His life and His perfection in exchange for all those who have not lived the law perfectly and are worthy of condemnation. His sacrifice is the exchange for their condemnation, His life is their reward for faith in Him, gratefulness to Him, love for Him, so that they too will live forever with Him and all those who likewise now live by faith. This faith is confirmed by the Spirit Who comes and resides within our hearts of flesh to comfort us when we sin, remind us of His pardon for our sin, and empower us to live by committing less sin so that God Who conquered sin for all can be seen by all as merciful, loving, and just among all humanity still living under the condemnation of their sin.