Let bygones be bygones because everybody knew that forgiveness was divine.
I am slow to listen to criminations among friends, and never espouse their quarrels on either side. My sincere wish is that both sides will allow bygones to be bygones, and look to the present & future only.
Nor is it wiser to weep a true occasion lost, but trim our sails, and let old bygones be.
Let bygones be bygones.