"This is the day which the Lord hath made; we will rejoice and be glad in it." Psalm 118:24
"This is the day that the Lord has made"--- today. He has not made tomorrow yet- tomorrow isn't here. Therefore, we are not to take thought for tomorrow. We are not to borrow trouble from tomorrow. We are not to worry about tomorrow. We are not to wonder about tomorrow. We are not to be fearful, anxious or upset about what may happen tomorrow because tomorrow doesn't exist yet. When you think about it, tomorrow never comes because when it gets here--- it will be TODAY!
Are you worrying about tomorrow? Are you concerned about what it may hold? If so, then you are allowing today to be stolen from you. Live today; enjoy today; make the most of today; be productive today; work on doing what you can do today while you have it because none of us are promised tomorrow.
Rejoice and be glad today. Put your trust and confidence in God today. Commit today to Him. Look to Him today. Cast your cares upon Him today. Remember tomorrow doesn't exist yet so leave it in the future. And remember also that when/if tomorrow does come that God will be as faithful then as He is today.
Have a great day. God has not made tomorrow yet, but He has given you today... so rejoice and be glad in it.
For further reading:
1 Peter 5:7