Our Scripture reading today is Luke 6:1-2, "And it came to pass on the second sabbath after the first, that he went through the corn fields; and his disciples plucked the ears of corn, and did eat, rubbing them in their hands. And certain of the Pharisees said unto them, Why do ye that which is not lawful to do on the sabbath days?"
According to Deuteronomy 23:25, "When thou comest into the standing corn of thy neighbour, then thou mayest pluck the ears with thine hand", the disciples had done nothing wrong.  They were not stealing due to the provision that was made for the poor.  It was not what they were doing, but it was when they were doing it that upset the Pharisees.  The Rabbis had made a list of dos and don'ts for the Sabbath.  The disciples broke four "laws": reaping, threshing, winnowing and preparing food.  So many things were added by man to what should and should not be happening on the Sabbath.
I am thankful we have God's Word to instruct us on how to live our lives.  As followers of Jesus Christ, we also have the Holy Spirit to teach us the Word of God.  He is the author of God's Word.  It is our responsibility to follow the dos and don't we find in the Word of God.  We must avoid adding to what God's Spirit has already written.  Revelation 22:18, "For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book:"