the heart

Jeremiah 17 : 7-10
7 "But blessed is the man who trusts in the Lord, whose confidence is in Him
8 He will be like a tree planted by the water that sends out its roots by the stream.
It does not fear when heat comes; its leaves are always green
It has no worries in a year of drought and never fails to bear fruit."
9 The heart is deceitful above all things and beyond cure. Who can understand it?
10 " I the Lord search the heart and examine the mind,
to reward a man according to his conduct, according to what his deeds deserve."