How do we keep God's Law?

How might we keep the Law and love one another without fail, without holding back? Setting our will to do it or making promises or resolutions has never worked before, and it won't work now.  How might we keep the Law which we've never yet kept before? But putting on the Lord Jesus Christ. That is it.  It is the only way.  It is in being loved, being forgiven, being fed the Holy Supper that not only is sin forgiven but faith is also strengthened.  In that  - those things that God has given for His church, for her faith and life - the Holy Spirit takes up residence and works do follow.  The only way for sinners like us to keep the Law is to have the Law kept for us.

From "God With Us, Advent, Christmas, and Epiphany Sermons" by David H. Petersen.  Page 22.