1 Chronicles 12:38
"All these men of war, that could keep rank, came with a perfect heart to Hebron, to make David king over all Israel: and all the rest also of Israel were of one heart to make David king."
Cross References (ranked by relevance)
Let your heart therefore be perfect with the LORD our God, to walk in his statutes, and to keep his commandments, as at this day.
And I will give them one heart, and I will put a new spirit within you; and I will take the stony heart out of their flesh, and will give them an heart of flesh:
For it came to pass, when Solomon was old, that his wives turned away his heart after other gods: and his heart was not perfect with the LORD his God, as was the heart of David his father.
I will behave myself wisely in a perfect way. O when wilt thou come unto me? I will walk within my house with a perfect heart.
Of Zebulun, such as went forth to battle, expert in war, with all instruments of war, fifty thousand, which could keep rank: they were not of double heart.
Also in Judah the hand of God was to give them one heart to do the commandment of the king and of the princes, by the word of the LORD.
Thy people shall be willing in the day of thy power, in the beauties of holiness from the womb of the morning: thou hast the dew of thy youth.
I beseech thee, O LORD, remember now how I have walked before thee in truth and with a perfect heart, and have done that which is good in thy sight. And Hezekiah wept sore.