Had We decreed for them, "Face yourselves," or "Leave your land," they would not have done so except for a few of them. If they had done what they were advised with, it would have been better for them and helped to strengthen them.
Translation endnotes
[4:66] The phrase traditionally being translated as "kill yourselves" can be read as "faqbilu anfusakum", that is "face yourselves" or "accept yourselves." Here, it is an alternative to leaving the land. It means, either look at the mirror and change yourselves or leave the land. See 2:54,84.