'Deceitfully' in the Bible

And now swear to me here by God that thou wilt not deal deceitfully with me, nor with my son, nor with my grandson. According to the kindness that I have done to thee, thou shalt do to me, and to the land in which thou sojournest.

And the sons of Jacob answered Shechem and Hamor his father deceitfully, and spoke because he had defiled Dinah their sister --