...we could obey the law perfectly (this includes both the law of Mose and the commandments of Christ).
This isnt correct.
The law was given to prove how sinful we all are.
That no one was righteous not one. Even if people had obeyed every
aspect of the law (and they didnt). They would have had to
continually offer animal sacrifices because there could never have
been enough animal sacrifices to take away the sin of the world.
The law was never about making us perfect, it was about exposing how
far we had all fallen. It was about showing the holyiness of God and giving
people some idea of the seriousness of sin. The law was a temporary poor
substitute until at just the right time, Christ could come into our world.
Romans 5:18-21 NLT
[18] Yes, Adam's one sin brings condemnation for everyone,
but Christ's one act of righteousness brings a right relationship
with God and new life for everyone.
[19] Because one person disobeyed God, many became sinners.
But because one other person obeyed God, many will be made righteous.
[20] God's law was given so that all people could see how sinful
they were. But as people sinned more and more, God's wonderful
grace became more abundant. [21] So just as sin ruled over all
people and brought them to death, now God's wonderful grace
rules instead, giving us right standing with God and resulting in
eternal life through Jesus Christ our Lord.