Luke 6:31 signals a new standard for the treatment of both friends and enemies. The treatment of those who cannot help us is one of the marks that distinguishes Christ-followers from others.
The measure God uses in return for justice is equal justice. The measure he uses for generosity is overflowing, pressed down, and shaken together. God is serious about encouraging generosity.
From the abundance of the heart the mouth speaks. This may be the key diagnostic principle in all the Bible. What is treasured in the heart is what comes out, whether good or bad.
Unlike the children's song, the one who hears and does Jesus' words is the wise builder with a strong foundation. It is not simply the person who "believes".