From the Greater to the Lesser

Paul reasons like this: since God did not spare his own Son, then sure he must and will freely give us all things with him. Why is that?
Paul is reasoning in Romans 8:32 from the hard to the easy, or from the greater to the lesser. God desired two things: not to see his Son made a mockery by sinneres; and not to see his peole denied infinite future grace. Surely it is more likely that he will spare his Son than that he will spare us. But no. He did not spare his Son.
What a truth! Giving us all things is the easy thing! Think on that every time you fear being denied something that owuld be good for you. Creating the world and running it for the good of his people is a relatively easy thing for God to do compared to handing over his Son to ridicule and torture. But he did it. Ann now all future grace is not only sure; it is easy.

Future Grace, by John Piper

Sin Canceled by Lawful Living?

"Sin is not canceled by lawful living, for no person is able to live up to the Law. The Law reveals guilt, fills the conscience with terror, and drives men to despair. Much less is sin taken away by man-invented endeavors. The fact is, the more a person seeks credit for himself by his own efforts, the deeper he goes into debt. Nothing can take away sin except the grace of God."

Commentary on the Epistle to the Galatians by Martin Luther
http://blueletterbible.org/Comm/martin_luther/Gal/Gal001.html

It Kills and Makes Alive

"Grace brings into the heart and entirely foreign element. That element does not improve and perpetuate. It kills and then makes alive. There is no continuity between the state of nature and the state of grace: the one is darkness, and the other is light; the one is death, and the other is life. Grace, when it comes to us, is like a firebrand dropped into the sea, where it would certainly be quenched were it not of such a miraculous quality that it baffles the waters and sets up its reign of fire and light even in the depths."

Grace: God’s Unmerited Favor by Charles Spurgeon

Whitaker House. 1996. Springdale , PA.