The Light guides, reveals and empowers. He does so through scripture and the indwelling Holy Spirit. In this way, those who are in Christ are never really in total darkness, though their circumstances might suggest otherwise.
The Light not only leads us at all times, but shines through us for all to see. This is how we become the light of the world. When everyone around us feels defeated because darkness has overtaken them, we testify to the ever-present Light, the Light of the World.
This Light within is not an extension of ourselves or some inner knowledge we hope to achieve. Rather, it is Christ in us, the hope of glory (Colossians 1:27). He has overcome the evil one and transferred us into His kingdom of Light.
Right now you may not see the light, but you can still have the Light. And unlike all man-made light, His will never be extinguished.