Well, yes, obligation to nothing, even God, was the essence of Adam's sin. And sin will always be opposed to God, to His very nature. As creatures who must remain in relationship with their Creator we're still obligated in any case; 'Apart from Me you can do nothing'. We're obligated to do what is right and just, meaning we're obligated to love God with our whole heart, soul, mind, and strength and our neighbor as ourselves. "Thou shalt love", properly understood, could be a concise summation of the gospel. The message of the New Covenant is simply that we cannot do it on our own-but that if we don't do it, by means of that relationship with God, then sin and the death it earns continues on. In the end we no longer feel the obligation the more we come to agree with and embrace it for ourselves, the more we come to embrace Him, IOW.