At times, Christians worry like the unbelievers. When we think and behave like the world, we will worry like the world. When we crave for things like the world, we will worry like the world. This happens when our mind is not centered on God. Because of that, our mind will always find cause to worry.
The English word "worry" originates from an old German word meaning to "strangle, or choke." That is exactly what worry does to you and I. Worry leads to mental and emotional strangulation. This in turn causes more mental and physical sufferings than any other causes. Worry might be the sin that most people, including Christians, commit more often than any other.
God expects His children to be different from the world. I'm always reminded of what the Lord Jesus said about this matter: "Therefore I tell you, do not worry about your life, what you will eat or drink; or about your body, what you will wear. Is not life more important than food, and the body more important than clothes? Look at the birds of the air; they do not sow or reap or store away in barns, and yet your heavenly Father feeds them. Are you not much more valuable than they? Who of you by worrying can add a single hour to his life? ... “And why do you worry about clothes? See how the lilies of the field grow. They do not labor or spin. Yet I tell you that not even Solomon in all his splendor was dressed like one of these. If that is how God clothes the grass of the field, which is here today and tomorrow is thrown into the fire, will he not much more clothe you, O you of little faith? So do not worry, saying, ‘What shall we eat?’ or ‘What shall we drink?’ or ‘What shall we wear?’ For the pagans run after all these things, and your heavenly Father knows that you need them. But seek first his kingdom and his righteousness, and all these things will be given to you as well. Therefore do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own.” (Matthew 6: 25-34)
I see Jesus giving us 3 reasons here why worrying is sin:
1.) Worrying is unfaithfulness to God.(v. 25)
It reveals no, little, or defective faith in God.
2.) Worrying is unnecessary.(vv.26-30)
It reveals that you do not fully trust our Father's promises.
3.) Worrying is unwise. (v. 34)
It reveals you're being mastered by circumstances or outside needs.
Does that mean that you don't do anything at all about your needs or future? Remember, there is a difference between "being concerned about the future" and "being worried about the future." "Being concerned about the future" means taking normal precautions and preparations for the future whereas "being worried about the future" involves obsessing and getting afraid about circumstances.
Instead of worrying about the future, there are healthy, constructive things that we can do. Jesus says, "Seek first the Kingdom of God and His righteousness, and all these things will be given to you as well." "Do not be anxious 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 minds in Christ Jesus"(Phil. 4:6-7).
If you believe that God can save you from sin, take you to heaven, and give you eternal life, then how can you not believe that God will take care of you the rest of your earthly days? Stop worrying now and place your complete trust in God and His promises!