One scriptural example that illustrates the need for a proper correlation between heart and mind is the Old Testament character, Amaziah. 

Second Chronicles 25:2 tells us: 
“He did what was right in the LORD’s sight but not completely.” 

His mind gave itself to doing right in the sight of the Lord-
– but his heart did not support his actions.

This lack of coordination proved to be his undoing: 
“After Amaziah came from the attack on the Edomites, he brought the gods of the Seirites and set them up as his gods.He worshiped before them and burned incense to them.” 

Now look at how the life of Amaziah ends:

“From the time Amaziah turned from following the LORD, a conspiracy was formed against
him…men were sent after him to Lachish, and they put him to death there.” 25:27. 

Notice the steps:

He was outwardly correct but inwardly uncoordinated.
His inner disunity showed itself in outer disloyalty.
This disunity resulted in his failure and death.

At the beginning, Amaziah does not appear to be a particularly bad individual-
– he just failed to be wholehearted in his commitment. 

He did all the right things outwardly-
– but his heart was not in them
– hence, his spiritual ruin.

We could say he missed his step by inches-
– but his fall was one of the worst ever recorded. 

If we are not held together by a single-minded devotion-
– our spiritual life can quickly go to pieces. 

Commitment to God demands cohesion-
– the cohesion of heart and mind.

“God my Father, help me to live a life of single purpose, with heart and mind moving together as one. Let me will the highest with all my being. In Jesus’ Name I ask this. Amen.”
(PA)