Steps toward legalistic bondage

Then Jesus said to the crowds and to his disciples, “The scribes and the Pharisees sit on Moses' seat, so practice and observe whatever they tell you—but not what they do. For they preach, but do not practice. They tie up heavy burdens, hard to bear, and lay them on people's shoulders, but they themselves are not willing to move them with their finger. (Matthew 23:1-4 ESV)

In their attempt to make the law relevant the Pharisees rules applying the law.  The rules then became binding and equal to the law.  This slowly draws one attention from trusting in Christ for our righteousness to trusting in rules for our righteousness.  Theses rules become heavy burdens as we attempt to follow them.  As we place value on them as truth, the become emotionally equal to or greater than the Scriptures themselves.   Our focus shifts from Christ as our source of righteousness to 'works of law' as our source of righteousness.  It is a slippery slope and dangerous.  It binds us up rather than frees us (Gal 5:1).