Behind Abraham’s attitude was his faith that God was ordering things. He believed God’s word to him “I am your very great reward” (Gen 15,1).
There was no need for him to live a life of strain and anxiety about loss or gain. If he trusted God, God’s plan would work out in his affairs. He didn’t want to have what God didn’t want him to have.
King David, a thousand years later found the same truth. He adopted Abraham’s outlook and enjoyed the great advantage of letting God take over.
He wrote a song of surprised gratitude (2 Samuel 23) and described God’s plan for him in his house as being “ordered in all things and sure” (v.5). Jesus put the principle of Abraham into His famous promise of the Sermon on the Mount, Matthew 6:33. “Seek first the Kingdom God and his righteousness and all these things will be given you as well”.
He said “Don’t worry about your life. Do not worry about tomorrow.”