Offers are conditional. For most firms, they are contingent on a clearing a conflicts and background check. These are essential steps that must be completed before the deal is done, even if you have already negotiated a starting date. The conflicts check can take longer than you anticipate (I’ve recently seen this take over a month). Be patient. You’ve come this far. You do not want to jeopardize your offer by doing the following things:
QUIT YOUR JOB
I know you want to get out there and start the next chapter in your professional life. Remember, your offer is contingent on a conflicts and background check. Should the offer fall through for any reason, you do not want to jeopardize your current position. It is easier to find a job with a job and proves much more difficult if you find yourself unemployed.