The True Source of Reality

Separating illusion from reality doesn’t usually happen all at once. What we experience as reality changes in different stages of consciousness. For those who decide to renounce the world completely, it’s possible to leap directly toward the goal. But even then there is no guarantee that perception has actually shifted.
A person may enter a monastery but if old perceptions get dragged through the door, the monastery holds the same traps as the material world: Ego.
Jesus wanted his disciples to come into union with God. Any other life was steeped in illusion. Ego keeps that illusion strong because “I, me, and mine” is so rooted in worldly affairs. The most worthwhile life is spent discovering your spiritual core and building your existence on it. If you do that, you will be first in the eyes of God even if you are last in the eyes of the world.
If you can perceive the light within, you will gain its fullness. But if you are blind to it, you will have none. The reality you find yourself in depends on you. The light is God’s reality, the dark is the absence of God.
Jesus wanted to share the unity he experienced with God, and therefore he often used the phrase abide in me. The parable of the grapevine elaborates on the point. Jesus declares that being cut off from God is sterile and fruitless. The sap that nourishes the vine and causes it to bear fruit is God, the source of life. By implication, the only life that escapes death is one that connects back to its ultimate source.