Our central air system has filters. Filters are designed to keep dust and dirt from re-circulating through the house. When they are cleaned, it’s obvious how well they do their job.
Our vehicles have air filters, too. A bit of irony, since automobiles cause so much air pollution.
Speaking of which, when I was in Taiwan I saw hundreds of motorists on scooters, motorcycles, even in cars, wearing masks. They were designed to filter out the particles in the air from all of those vehicles.
Recent photos from Mexico, and older ones from Hong Kong, showed people wearing masks hoping to filter out the viruses for H1N1 and SARS.
Filters only work as good as their design. Well-designed filters keep out particles down to microscopic levels. If a filter was a foot square and had only one thread, it might keep a cat out, but any sized particles.
Did you think that example was a bit unrealistic? How about filtering out things that go into our minds? Often there isn’t even that one thread to keep out damaging particles.
The Bible tells us what should be in our minds:
Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things. (Philippians 4:8 KJV)
How many things are in our minds that do not pass those filters? How do we build a good filter?
Thy word have I hid in mine heart, that I might not sin against thee. (Psalms 119:11 KJV)
So shall I have wherewith to answer him that reproacheth me: for I trust in thy word. (Psalms 119:42 KJV)
Thy word is a lamp unto my feet, and a light unto my path. (Psalms 119:105 KJV)
When we think we cannot do this filtering, when we believe the worst in our lives, Paul continued with this understanding of himself:
I can do all things through Christ which strengtheneth me. (Philippians 4:13 KJV)
Which is only confirmation of what Christ has promised to us all:
For with God nothing shall be impossible. (Luke 1:37 KJV)