[Jesus continued his condemnation of the teachers of religious law and the Pharisees:] "Blind guides! What sorrow awaits you! For you say that it means nothing to swear 'by God's Temple,' but that it is binding to swear 'by the gold in the Temple.' Blind fools! Which is more important — the gold or the Temple that makes the gold sacred? And you say that to swear 'by the altar' is not binding, but to swear 'by the gifts on the altar' is binding. How blind! For which is more important — the gift on the altar or the altar that makes the gift sacred? When you swear 'by the altar,' you are swearing by it and by everything on it. And when you swear 'by the Temple,' you are swearing by it and by God, who lives in it. And when you swear 'by heaven,' you are swearing by the throne of God and by God, who sits on the throne."
— Matthew 23:16-22 NLT
Of course the bottom line for Jesus is that we shouldn't have to swear by anything: Our "yes," our word, should be enough.* But to make matters worse, the teachers of religious law and the Pharisees went beyond swearing to a developed theology of what things by which you swear are most important.
Jesus is angry because the simple truth has been complicated and compromised by petty distinctions in legal terminology. Jesus' anger should be felt by believers today. In an age of sound bites, spin, and hedging the truth through "legalese," we as Christians must be a people who simply speak the truth openly, honestly, and without compromise, but always in love.