In our Gospel reading today, Jesus blasts the Pharisees in a moment of righteous anger. The Pharisees focused on the fine details of God's law (as they interpreted it) while ignoring the spirit of God's law. In particular, He goes after them for their insistence on details such as the exact tithing of herbs while ignoring essential values of the Torah: justice, mercy, and faith. Jesus insisted that people value and practice what matters most to God.
Indeed, it is essential for us as Christians, that we keep returning to the fundamentals, to the true spirit of the Gospel, so that we will know and do what God wants of us.
In the Book of the Prophet Micah we hear the words, "You have been told, O mortal, what is good, and what the LORD requires of you: Only to do justice and love goodness, and to walk humbly with your God." [1] These were the ideals Jesus exemplified in His life and His death. To live by them is to "put on the LORD Jesus Christ" [2], which is our essential vocation. +
[1] Micah 6:8
[2] Romans 13:14