The heart is deceitful above all things and desperately wicked: who can know it? I the Lord search the heart, I try the reins, even to give every man according to his ways and according to the fruit of his doings.
Jeremiah 17:9, 10
"We are here on earth and in a sinful condition. 
We admit that we are not in that spiritual condition that we ought to be and so we will search our hearts and put away all the wickedness that we can find in them.
We cannot do it, for the heart will deceive us every time.
--Yet God can search the heart and if we will take the result of His searching, great will be our joy."
E.J. Waggoner