Hebrews 4:11-16

Indeed, the word of God is living and active, sharper than any
two-edged sword, piercing until it divides soul from spirit, joints from
marrow; it is able to judge the thoughts and intentions of the heart.
(4:12)

The authors of Scripture show a frequent interest in the heart,
using the word to describe the will both of God and of humans.
Deuteronomy speaks of “circumcision of the heart,” a concept that
St. Paul repeats centuries later. Hebrews tells of “the intentions of
the heart,” and of how Jesus strips away our pretenses. John the
Baptist, while not mentioning the heart directly, says that his joy has
been fulfilled by the advent of Jesus the Messiah.

When Scripture mentions the heart, I hear this chanted phrase from
Eastern Orthodox worship: “Wisdom! Let us attend!” At the mention
of the heart, I sense the Holy Spirit drawing near, and inviting me to
draw near, to impart what God wants from me: in my mind, in my will,
in my daily choices, in my actions. And I hear two words from revival
hymnody: trust and obey.

—Douglas LeBlanc