Refuge
In brief, a source of refuge is something that, when we place our hopes in it, it actually gives us refuge, gives us protection and helps us. And that which is helped is principally the mind. It is the mind that needs to be helped because all of our suffering and difficulties stem from the mind. If the mind is not given help and protection, then there is no other way we can truly be helped.
Whether the three jewels or our lama, the correct way of relating to them as a source of refuge begins with knowing their qualities: what are these sources of refuge, and what qualities do they possess? In what manner are they able to give us refuge and what is that refuge?
The actual sources of refuge are renunciation, bodhicitta, and wisdom. As beginners, this is the way we should relate to the sources of refuge. In truth there is nothing other than these which can give us refuge.