>Do men gather grapes from thorns?
Or figs from thistles?
Even so every good tree brings forth good fruit;
but a bad tree brings forth bad fruit
Matthew 7:16-18

>Either make the tree good and his fruit good,
or else make the tree bad and its fruit bad;
for the tree is known by its fruit.
Matthew 12:33   [Romans 9:21-22,  2 Timothy 2:20-21, Psalm 119:9] 

>For every tree is known by its fruit;
because from thorns, men do not gather figs,
and from a bramble bush men do not gather grapes,
a good man out of the good treasure of his heart
brings forth that which is good...
for out of the abundance of the heart, the mouth speaks
Luke 6:44-45

>Now, the parable is this:
The seed is the word of God.
Luke 8:11

>Those by the wayside are they that hear,
but then comes the devil and takes the word out of their hearts,
(he does so by confusing them so that they don't understand the word; Matt 13:19)
lest they should believe and be saved.
....
they on good ground are they, which in a noble and good heart,
having heard the word, keep it, and bring forth fruit with patience.
Luke 8:12-15


Therefore good fruit are people that hear the word of God and grow to produce more seed, resulting in other people also producing seed.