The LORD said in HIS Heart...

...I will not again curse the ground any more for man's sake; for the imagination of man's heart is evil from his youth; neither will I again smite any more every thing living, as I have done.

This was Day 3 - from Genesis 8:21 - I know God is not a 'physical' being, He doesn't really have any physical attributes, yet numerous times in Scripture He refers to body parts. Yet He records for us that He 'spoke' in His heart.

Another vein of thinking - who or where else did someone 'say in their heart' and what does it mean to 'say something in your heart?'

Abraham - Gen_17:17 Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?

Esau - Gen_27:41 And Esau hated Jacob because of the blessing wherewith his father blessed him: and Esau said in his heart, The days of mourning for my father are at hand; then will I slay my brother Jacob.

David - 1Sa_27:1 And David said in his heart, I shall now perish one day by the hand of Saul: there is nothing better for me than that I should speedily escape into the land of the Philistines; and Saul shall despair of me, to seek me any more in any coast of Israel: so shall I escape out of his hand.

Jeroboam - 1Ki_12:26 And Jeroboam said in his heart, Now shall the kingdom return to the house of David:

Wicked - Psa_10:6 He hath said in his heart, I shall not be moved: for I shall never be in adversity.

Wicked - Psa_10:11 He hath said in his heart, God hath forgotten: he hideth his face; he will never see it.

Wicked - Psa_10:13 Wherefore doth the wicked contemn God? he hath said in his heart, Thou wilt not require it.

Fool - Psa_14:1 The fool hath said in his heart, There is no God. They are corrupt, they have done abominable works, there is none that doeth good.

Fool - Psa_53:1 The fool hath said in his heart, There is no God. Corrupt are they, and have done abominable iniquity: there is none that doeth good.

Now the question, what am I saying in my heart?  Am I meditating upon His Word? Taking every thought captive?  How about you?