What does Luke 12:31 mean?

This text was written in a culture where a poor person might own only one set of clothing. They would spend much of the day working for, finding, and preparing food just for that day. Most of the population were slaves or laborers on other people's land. Finding food to eat and clothes to wear was a significant endeavor.

Ever willing to challenge His students, Jesus tells His disciples they are not to worry about such things. God provides for the most banal examples of His creation—scavenger birds and grass—and He knows what His own children need. The days of their lives are more important. They are called to seek God's great, eternal kingdom, not try to hold on to their own earthly hovel.

The kingdom of God can be difficult to explain. It is the manifestation of God's power and sovereignty over His creation. Whenever we honor Him as our God, we are presenting the kingdom. God called His disciples to declare its coming (Luke 10:9) and to pray for its fulfillment on earth (Matthew 6:10). It was inaugurated with Jesus' first coming and will be fulfilled with His second. At its fulfillment, it will never be destroyed. It is filled with riches for God's followers that will never fail (Luke 12:32–34).

That "these things will be added to you" has many different interpretations. Some think it means that if we serve God, He will provide us with food and clothing. Others think this is a kingdom promise, and we will receive what we need in eternity. "Prosperity gospel" advocates pervert the message by claiming that if people donate to certain leaders, God will give them riches. God doesn't promise His followers that they will never starve or be without clothing. Nor does He promise earthly wealth. He will provide for us exactly what we need to fulfill His plan. Our submission to His will, and our part in His kingdom, will earn us a permanent treasure that can never be destroyed.