'Bygone' in the Bible

I have considered the ancient days,The years [of prosperity] of long, long ago.

then I will bring you down to bygone people, to be with those who descend to the pit. I will make you live in the lower parts of the earth, among the primeval ruins, with those who descend to the pit, so that you will not be inhabited or stand in the land of the living.

whom God did set forth a mercy seat, through the faith in his blood, for the shewing forth of His righteousness, because of the passing over of the bygone sins in the forbearance of God --