It will be a great benefit to us in every way, to learn this lesson

(J.R. Miller, "Morning Thoughts" 1906)

"Do not worry about anything — but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus." Philippians 4:6-7

Learning not to worry, is one of the lessons that every Christian should master.

Worry is a terribly wasteful experience:
   it uses up the strength we need for our duty,
   it unfits us for doing our work well,
   it is dishonoring to God, for He has promised to care for us, if only we do His will faithfully,
   it is utterly fruitless, for it does not take away the things that it frets over.

The Bible gives many lessons on the subject — but none that makes plainer just how we are to eliminate worrying from our life, than what Paul here tells us to do.

First of all, we are simply not to worry: "Do not worry about anything."
There is no room for exceptions, special circumstances, and all that.
We are not to worry about anything.

What then shall we do with the matters that we are disposed to worry over? Put them into the hands of God in prayer — and leave them there! If we do this — then the peace of God will guard our hearts and thoughts from all anxiety.

It will be a great benefit to us in every way, to learn this lesson.