Little boy comes clomping around the corner with his tiny feet in Dad’s huge shoes.  It’s an unselfconscious act, cute, but with a profound heartbeat.  It says, “One day, I want to be just like Dad; when I get big I want to fit in his shoes.”  Same thing with girls and Mom.  
This pertains to a verse of Scripture that initially makes me recoil.

And everyone who thus hopes in him [Jesus] purifies himself as he is pure.  (1 John 3:3)

The word I most readily associate with purity is “boring.”  It reminds me of being forced as a child to wear an itchy wool suit and sit at the dinner table with my hands folded and my mouth shut. Why would I want to do that to myself now, as an adult?  Give me jeans and fire up that motorcycle…

The problem is twofold: 1) we don’t have a good understanding of what purity is, and, 2) we don’t understand the right motivation for purifying ourselves.  

Jesus modeled perfect purity but, as far as I’ve been able to determine, never wore a wool suit.  He was not One to follow pointless, restrictive rules derived from other people’s inhibitions, but lived with an easy and attractive “rightness.”  When you think purity, think about how comfortable Jesus was inside His own skin, how He effortlessly lived in harmony with God’s perfect design.

The verse that preceeds the one I quoted puts the motivation for purifying ourselves in the proper perspective.  John began his thought with these words:

Beloved, we are God’s children now, and what we will be has not yet appeared; but we know that when he appears we shall be like him, because we shall see him as he is.   (1 John 3:2)

We tend to think of reluctantly struggling to be pure so God won’t be angry with us.  Instead, think about happily clomping around in Daddy’s shoes, with the childlike hope and trust that says, one day, I’ll be like Him.