Origin
It was first recorded in 1711.
Explanation
This is a proverb expressing the idea that forgiveness is a worthy response to human failings. Every human can make a mistake, so we should forgive him/her, just as God is said to show His divine mercy in forgiving sinners.You should not be too harsh with someone who makes a mistake, because all human beings make mistakes.
Examples
You’d think he could find it in his heart to forgive her. To err is human and all that.
Jill : How could you let my dog get out when I told you a hundred times that he should stay in the house!
Ellen : To err is human; to forgive divine.