'Foolishly' in the Bible

And Samuel said to Saul, Thou hast done foolishly: thou hast not kept the commandment of Jehovah thy God which he commanded thee; for now would Jehovah have established thy kingdom over Israel for ever.

And Saul said, I have sinned: return, my son David; for I will no more do thee harm, because my life was precious in thine eyes this day: behold, I have acted foolishly, and have erred exceedingly.