Calvary was the place where The Lord God Jesus Christ was Crucified and died.
Why?
To pay the death penalty for our sins.
Jesus never sinned. Therefore He was able to be the perfect unblemished substitutionary sacrifice to atone/pay for the sins of sinners.
Anyone who accepts that free gift of His death in payment for your, my, anyone's sins will be forgiven of their sins because Christ's death served as the substitute payment.
HERE'S THE LINK to Lead me to Calvary
