What are the stages to this ability to see God in truth? Saint Theophan tells us that when this stage of our spiritual life comes, it comes without any effort or prior exercise, it will be like this:
A song to God will be born in the heart, pour out from your mouth, and fly towards heaven. That is a song of glorification, thanksgiving, and every kind of prayer. If this has begun to happen to you, then know that you are already in your place, in the rank of angels, continuously glorifying and hymning God Whom they see noetically.
As we reach the higher stages of prayer we will find there comes a time when the mind prays without any effort, without the use of our willpower. Saint Theophan explains this way,
This of course is mental prayer. Mental prayer little by little warms up the heart and ushers it into another prayer—prayer of the mind and heart. The heart, having become accustomed to prayer under the influence of the mind, and having warmed up, begins of itself to advance to prayer and to draw the mind into it. This is prayer of the heart—the true prayer, as it ought to be, a prayer which encompasses the whole nature of a man; for where the heart is, there is the whole person. This condition reveals itself by a drawing within, which occurs during prayer, reading, reflection, and, even without all of this, during any pursuit.For most of us reading this, including myself, this kind of prayer of the heart is something that we yearn for. But it is not something we can force. When we are properly prepared God will give us this gift.
But one ought to know that it is not the fruit of the labor of praying alone, but a consequence of the whole God-pleasing life, of all the labors of doing good and asceticism, and it comes to light when the heart begins to approach purity.
The Prophet David says to pray,
Create in me a clean heart, O God, and renew a right spirit within me (Ps 50:10)
My lips shall pour forth a hymn when Thou has taught me Thy statues. (Ps 118:171)
Reference: Psalm 118: A Commentary by Saint Theophan the Recluse, pp 335-336