Cast all your anxiety on him because he cares for you.
1 Peter 5:7
We can cast our cares on the Lord because we know that God is concerned about every detail in our lives and He cares for us deeply.
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 your minds in Christ Jesus.
Philippians 4:6-7
Not to be anxious is a command and to disobey a command is sin. We are to always trust God and never be anxious about the things of life. It does not mean that we become irresponsible. But that we do what we are capable of doind at that moment and leave the rest to God to work things out in His own time.
but the worries of this life, the deceitfulness of wealth and the desires for other things come in and choke the word, making it unfruitful
Mark 4:19
Life has its worries and if we dwell on those worries then it will choke the word of God in us. We will find it difficult to trust God and be happy.
Therefore do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own
Matthew 6:34
Everyday has its own set of problems and cares. We are not to worry about tommorow but concentrate our energies in solving the problems of the day.
So do not worry, saying, ‘What shall we eat?’ or ‘What shall we drink?’ or ‘What shall we wear?
But seek first his kingdom and his righteousness, and all these things will be given to you as well
Matthew 6:31, 33
We are not supposed to worry about anything but instead cast all our cares and worries on Him. This is a sign of trust and faith in God and it pleases Him. Without faith no man can please God. When we have faith we refuse to worry or be anxious about anything because we believe that all things are going to work out well. And the pain or problem we may be going through has been permited by our Father because He seems it to be best for us.