All look to you to give them their food at the proper time.
When you give it to them, they gather it up;
when you open your hand, they are satisfied with good things. (Psalm 104:27-28)
The eyes of all look to you, and you give them their food at the proper time.
You open your hand and satisfy the desires of every living thing. (Psalm 145:15-16)
"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)
We pray for God to supply our daily needs so that we come to know that he is the only source of everything that is good.
[God] has not left himself without testimony: He has shown kindness by giving you rain from heaven and crops in their seasons; he provides you with plenty of food and fills your hearts with joy. (Act 14:17)
[God] himself gives all men life and breath and everything else. (Act 17:25)
Every good and perfect gift is from above, coming down from the Father of the heavenly lights, who does not change like shifting shadows. (James 1:17)
If God is going to give us all these things, why do we need to pray for them? Because by praying we realize that neither our work or worry nor God's gifts can do us any good without his blessing.
He humbled you, causing you to hunger and then feeding you with manna, which neither you nor your fathers had known, to teach you that man does not live on bread alone but on every word that comes from the mouth of the LORD. (Deuteronomy 8:3)
Better the little that the righteous have
than the wealth of many wicked; (Psalm 37:16)
Unless the LORD builds the house,
its builders labor in vain.
Unless the LORD watches over the city,
the watchmen stand guard in vain.
In vain you rise early
and stay up late,
toiling for food to eat—
for he grants sleep to those he loves. (Psalm 127:1-2)
Therefore, my dear brothers, stand firm. Let nothing move you. Always give yourselves fully to the work of the Lord, because you know that your labor in the Lord is not in vain. (1 Corinthians 15:58)
By praying to God for our daily provision we are showing our dependence upon him for our every need. We need his help to give up our trust in creatures and to put our trust in him alone.
Cast your cares on the LORD
and he will sustain you;
he will never let the righteous fall. (Psalm 55:22)
This is what the LORD says:
"Cursed is the one who trusts in man,
who depends on flesh for his strength
and whose heart turns away from the LORD.
He will be like a bush in the wastelands;
he will not see prosperity when it comes.
He will dwell in the parched places of the desert,
in a salt land where no one lives.
But blessed is the man who trusts in the LORD,
whose confidence is in him.
He will be like a tree planted by the water
that sends out its roots by the stream.
It does not fear when heat comes;
its leaves are always green.
It has no worries in a year of drought
and never fails to bear fruit." (Jeremiah 17:5-8)
Keep your lives free from the love of money and be content with what you have, because God has said,
"Never will I leave you;
never will I forsake you."
So we say with confidence,
"The Lord is my helper; I will not be afraid.
What can man do to me?" (Hebrews 13:5-6)