The Israelites of long ago tended to be anxious about what they would eat and drink and how they would fare against their After years of slavery, they looked first for human solutions to their needs and problems. But they are to be God's people, and as such they must learn that if they put God first in their lives, he will watch over them.
Read Luke 12:16-31. How is this concept of giving priority to God preserved in the New Covenant?
This is a difficult one to address with practical situations in mind. The practical situations are primarily dictated by our culture and people around us. The statement that "God will protect us and give our needs" (as the parable in the Gospel of Luke tries to tell us), requires an understanding and conviction what "our needs" are. If I perceive that "my need" is to have 10 Million in my bank account, then the parable is meaningless. I am basically rejecting our Lord's teaching. Right? do you all agree? I am very curious to see what you all think about this topic. However, if my need is to live a happy life with minimal wealth to achieve that happiness, then it is easier to adhere to the parable our Lord gives us.
We all will have, to some varying degrees, problem following Jesus' teaching on this topic. To strictly follow His teaching, we need to be a monk (like the Franciscans).