Spiritual knowledge is like a house built in the midst of Greek and worldly wisdom, in which house, like a tightly locked trunk, there is the knowledge of the divine Scriptures, and the unutterable treasure hidden in this knowledge of the Scriptures, that is, Divine grace. Those who enter this house cannot see this treasure if the trunk is not opened for them, but this trunk cannot be opened by any human wisdom. This is why people who think in a worldly way do not know the spiritual treasure which lies in the trunk of spiritual knowledge, And just as someone who lifts this trunk on his shoulders cannot by this alone see the treasure which is inside, so also even if someone were to read and learn by heart the divine Scriptures, and could read them all like a single psalm, he cannot by this alone acquire the grace of the Holy Spirit, which is hidden in them. For just as what is hidden in the trunk cannot be revealed by the trunk itself, so also what is concealed in the divine Scriptures cannot be revealed by the Scriptures themselves.
St. Symeon the New Theologian