“The truth is that God isn’t concerned with any kind of obedience; he’s concerned with a certain kind of obedience. What motivates our obedience determines whether or not it is a sacrifice of praise … If any kind of obedience, regardless of what motivates it, is what God is after, he would have showcased the Pharisees and exhorted all of us to follow their lead, to imitate them. But he didn’t … External righteousness is something we can all achieve on our own with a little self-discipline and a lot of self-righteousness. But Jesus wants us to see that regardless of how well we think we’re doing or how righteous we think we’re becoming, when “You therefore must be perfect, as your heavenly Father is perfect” becomes the standard and not “how much I’ve improved over the years”, we realize that we’re a lot worse than we fancy ourselves to be–that unrighteousness is inescapable, that “even the best things we do have something in them to be pardoned … Only when our understanding of righteousness “exceeds that of the Scribes and Pharisees” and goes beyond outer conduct, will we see the  impossibility of achieving our own righteousness and the necessity of receiving Christ’s righteousness. There is nothing that sinners hate more than to be told that there’s nothing they can do, that everything has been taken out of their hands, that no matter how hard they try, their best is never good enough. And yet, we’ll never be free until we give up fighting for a righteousness we can claim as our own.”

-Tullian Tchividjian, read more here