All unsaved persons have an evil heart of unbelief.
Hebrews 3:12
Beware, brethren, lest there be in any of you an
evilheart of unbelief in departing from the living God;
For saved persons, they have been given the new heart.
Hebrews 10:22
let us draw near with a true
heart in full assurance of faith, having our
hearts sprinkled from an
evil conscience and our bodies washed with pure water.
Luke 6
43 “For a good tree does not bear bad fruit, nor does a bad tree bear good fruit. 44 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. 45 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.
See you are either the good tree or the bad tree, a bad tree cannot bear good fruit. Either make the tree good and its fruit good, or make the tree bad and its fruit bad. There is no inbetween state of existence.
Matthew 7:16-19New King James Version (NKJV)
16 You will know them by their fruits. Do men gather grapes from thorn bushes or figs from thistles? 17 Even so, every good tree bears good fruit, but a bad tree bears bad fruit.
18 A good tree cannot bear bad fruit, nor can a bad tree bear good fruit.
19
Every tree that does not bear good fruit is cut down and thrown into the fire.
Matthew 12:33-34New King James Version (NKJV)
A Tree Known by Its Fruit
33 “Either make the tree good and its fruit good, or else make the tree bad and its fruit bad; for a tree is known by
its fruit.
34 Brood of vipers! How can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks.
Those who bear good fruit to God are speaking it from their 'good' heart that God has given to them. God has ordained His people to bear good fruit which includes speaking the truth in Christ.