My Dad taught me about filters. I used to build the air conditioning kind at his shop in the summers. They came in standard sizes and custom too. 

They had three parts; a square (or rectangular) piece of polyester, two pieces of metal grill (the same size as the polyester) and four pieces of chipboard which would form the filter frame. 

My Dad started me out early when I'd visit the shop. He'd let me fold stacks of chipboard. I later advanced to cutting the polyester, which we called media. Getting the accurate measurement was a must. 

 It was a few years before I had my own station where I was making filters. 

Here's how we made them if you're interested: 

I'd place the four pieces of chipboard inside a secure a metal frame (making a square border), then I'd quickly add strips of hot glue to help secure the bottom piece of grill, which came next, and then the piece of media. Next came the second piece of grill. Then I'd pick up an air-powered staple gun and fold the chipboard, stapling the corners and sides to create an enclosure. Voila. 

I helped keep the air inside stores and homes clean. 

That's the only purpose of the filter. It traps dust and other unhealthy microscopic floaters inside the filter's media so that it doesn't flow through the vents and into the air that you breathe. Pretty nifty. 

Your filter only works if you keep it clean. My dad hardly ever goes anywhere without checking the filter. In public places he casually glances at the vent. If he comes to my house, he opens the vent. He then usually shakes his head and pulls out a dust corroded filter that bit the dust long ago...pun intended. He makes me a new one. 

People have filters too. Or else they're supposed to. 

 You've heard it said, "She has no filter" referring to someone who vomits strange, off-topic or unkind words on poor unsuspecting victims. 

In people, I visualize the "word filter" being somewhat like a flap. The idea is that the filter/flap closes off careless words that attempt to enter the mouth channel. It traps the words before they enter the air. 

Maybe people who speak too freely  don't have a filter....or MAYBE, they have a delayed flap. I'm pretty sure I do. The flap usually closes the second the words escape my mouth. One second too late. 

Words AND THEN the flap. 

The person I'm talking to has that "Where did that come from?" look. "It's my flap," I want to say. It's faulty. 

I'm in good company though. My favorite character in the Bible had the same problem. (Maybe that's why he's my favorite.)

Hint: He verbally denied Christ three times before the cock crowed even though he had a warning that he would. 

Yep. Good old Peter

I'd like to think that Peter meant it when he answered "Never Lord" when Jesus warned him. (I'd never say I didn't know you) 

Several days ago I read Mark's account of the transfiguration in chapter 9. In verse five, Peter has just suggested that shelters be built for Jesus, Moses and Elijah. I love verse six in parenthesis, which to me says "this can't be left out". 

Verse six says,

(He did not know what to say)

In other words, he didn't know what to say, but he said something anyway. 

Flap problem.

 Words that could've  been stopped by the filter came on through. Peter is notorious for saying stuff that displayed his humanity. 

Thankfully his willingness to follow Christ outshines his lack of the ability to use caution in crafting words. 

 I don't exactly know where our each person's flap is located. Maybe it's in different spots for different people. All of us have words and thoughts without merit.  It's good when we can hold them captive. But we're responsible for our thoughts too. 

Thankful that we have a Father that checks our filter at the heart level. He cleans up the place, giving health to us and those around us. May we give him such an invitation. 

Create in me a pure heart, O God, and renew a steadfast spirit within me. Psalm 51:10