'Shall' in the Bible

And Isaac answereth and saith to Esau, 'Lo, a mighty one have I set him over thee, and all his brethren have I given to him for servants, and with corn and wine have I sustained him; and for thee now, what shall I do, my son?'

none is greater in this house than I, and he hath not withheld from me anything, except thee, because thou art his wife; and how shall I do this great evil? -- then have I sinned against God.'