In the last book of the Old Testament {Malachi}, God reminds His people of a great principal of His, that carries with it a great promise from Him. A promise that all of us want HAVE, but a principal that few of us want to HEAR. Knowing our human proclivity to remove ourselves from this principal, God issues a promise to us and says 'SEE IF I WONT...'; which isn't a threat, but an invitation.