Sunday service - Good tree, Bad tree

My text for the two Sunday services was taken from Luke 6:43-45

“For a good tree does not bear bad fruit, nor does a bad tree bear good fruit. For every tree is known by its own fruit. For men do not gather figs from thorns, nor do they gather grapes from a bramble bush. A good man out of the good treasure of his heart brings forth good; and an evil man out of the evil treasure of his heart brings forth evil. For out of the abundance of the heart his mouth speaks."

A few important principles I learn from this text:

1. All bear fruit. Some bad, others good but what appears good may not necessarily be good
• God loves at the motive or intention behind the action
• Cain's offering was rejected because the motive was wrong.
• 1 Sam 15 - Saul was rejected because his intentions were wrong although his actions seemed right.
2. Action is important but for God the intention behind the action is even more important.
1. Fruit in the Bible speaks of three important things:
1. Conduct
2. Character
3. Souls 
4. Jesus says words are important as well.
3.  If intentions really matter, our words are an indication of our intention
4. If the above is rue, our hearts determines our words.
1. For out of the abundance of the heart his mouth speaks.

How do we guard our hearts so that we bear good fruit?