Mercy is part of the very essence of creation, especially material creation. This is true, I believe, in what I have already mentioned: in our embodied nature God has "spun off", so to speak, the principle of our continued mortal existence into the network of secondary causalities we call nature. It is true that we continue to exist only because God directly, perfectly, lovingly wills that we do so--the secondary causality of nature does not usurp, replace, or contradict the perfect will in God's primary causality. Yet God willed that our evil should not lead to final and complete dissolution, either in the case of the human race or for individuals.
Of course, the meaning of the body is radically more complex, beautiful, and God-glorifying than simply the buffer between our evil acts and the damnation which would otherwise be the direct consequence. But it does have that quality. It is a fore-ordained irony that the flesh which is the groundswell of our concupiscible passions and so often leads us to sin, is also always the very vehicle made available to our freedom to carry us back to God.
Of all of God's qualities--omnipotence, omnipresence, omnibenevolence, undivided, unextended, eternal, etc.--mercy is what most distinguishes the God of faith from the god of the philosophers. Mercy is the essence of religion, especially true religion. Everything that God does, even punishment, even (I believe) damnation, has as its first fact, this quality of mercy (I am convinced of a minority belief that oblivion cannot be preferable to damnation).