“And he humbled thee, and suffered thee to hunger, and fed thee with manna, which thou knewest not, neither did thy fathers know; that he might make thee know that man doth not live by bread only, but by every word that proceedeth out of the mouth of the LORD doth man live.” - Deuteronomy 8:3
The prayer for God to “give us this day our daily bread” should be understood to mean that we are asking God to give us both spiritual and literal bread. The spiritual bread, which is the word of God, is more important. It teaches man what to do so as to get life, which ordinary bread cannot do. (Isaiah 55:1-3; Matthew 16:6-12; etc.) However, literal food is also important as it is needful for daily sustenance. No human being can stay or function for long without food. It was for this reason God Almighty fed the Jews with manna in the wilderness. (Exodus 16:16-35) Also, Jesus Christ miraculously fed 5000 people with five loaves of bread and two small fishes. – John 6:1-14.
It should be noted that Jesus taught us to pray for our daily bread, that is, for us to have food enough for the day. We should not ask for or set our minds on having so much more than we need for our sustenance, for that would amount to greed, which could lead people to sin and untimely death. We should remember the words of Agur who prayed God to feed him with food “convenient” for him. - Proverbs 30:8.
This aspect of the Lord's prayer also means that we should be contented with what God has provided for us. -1 Timothy 6:6-8.