Kempis concludes his chapter on rash judgment (1,14) with the wise words above.  A person who appeals to reason when coming to a negative quick judgment is neither enlightened, nor subject to the Lord, nor filled with ardent love.  We are to imitate Jesus in mercy (see Lk 23:34), not the devil in accusation (see Rev 12:10).  This contrast between judgment and mercy is best expressed by James in his epistle:

For the judgment is merciless to one who has not shown mercy; mercy triumphs over judgment. (Jas 2:13)

In expanding on what He meant (in the headline), Jesus, among many other sins, lists “malice, … envy, … arrogance” (from today’s Gospel, Mk 7:14-23).  Are these not often the cause of our snap judgments?  Thinking ourselves better than others or tearing others down in order to build ourselves up?  What is the proper disposition we are to maintain?  Well, we look to the last word of Kempis’s: love.  Love does not defile us or the other.  How is this made possible for us broken humans?  By relying “upon the power of Jesus Christ.”

Let us never stop begging for God’s mercy and grace — for ourselves and for others — to overcome the temptation to defile ourselves by defiling others.

Contemporary Jesus (2010) by Jerry Bacik