The animals you choose must be year-old males without defect, and you may take them from the sheep or the goats. Exodus 12:5

“If the offering is a burnt offering from the flock, from either the sheep or the goats, he is to offer a male without defect." Leviticus 1:10

For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord. Romans 6:23

The sacrificial system in the Old Testament involved a male goat or sheep who was without physical/bodily defect (Exodus 12:5, Leviticus 1:10). The sacrifice, which did not sin, died for person who had sinned. In essence, the sinless sacrifice died for, in place of, the sinner who brought it to die in place of himself.

We should all die for our own sins, as indicated in Romans 6:23. The thieves on both sides of the cross attest to this. They died for their own sins.

Many martyrs in history died for a cause. Their deaths had meaning, but could not satisfy God’s requirement for a sinless sacrifice since some time in their life they sinned.

Jesus died for those had sinned. He fulfilled those Old Testament requirements for a sacrifice – a male sacrifice without defect (sinless). He took on the punishment of death for us since he was not dying for his own sins.