Keep your heart with all diligence

Proverbs 4:23

Above all else, guard your heart, for it is the wellspring of life.

Luke 6:45

The good man brings good things out of the good stored up in his heart, and the evil man brings evil things out of the evil stored up in his heart. For out of the overflow of his heart his mouth speaks.

Matthew 12:34-35

34 You brood of vipers, how can you who are evil say anything good? For out of the overflow of the heart the mouth speaks.

35 The good man brings good things out of the good stored up in him, and the evil man brings evil things out of the evil stored up in him.

Mark 7:21-23

21 For from within, out of men's hearts, come evil thoughts, sexual immorality, theft, murder, adultery,

22 greed, malice, deceit, lewdness, envy, slander, arrogance and folly.

23 All these evils come from inside and make a man ‘unclean.’”

Jeremiah 17:9

The heart is deceitful above all things and beyond cure. Who can understand it?

Matthew 15:19

For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false testimony, slander.

Psalms 139:23-24

23 Search me, O God, and know my heart; test me and know my anxious thoughts.

24 See if there is any offensive way in me, and lead me in the way everlasting.

Proverbs 23:19

Listen, my son, and be wise, and keep your heart on the right path.