Service of the Absolute Truth
means to render service
unto the Absolute Personality of Godhead.

The neophyte devotee has no capacity to approach
the Absolute Personality of Godhead with his present,
imperfect,
material senses.
By submissively serving the bona fide spiritual master
who is a bridge between the Lord
and the neophyte,
he is automatically fixed up into
the transcendental service of the Lord.

And, by so doing even for some days
the neophyte gains
knowledge which leads him
ultimately
to extricate himself from the perpetual habitation
in the material world after world after world
and be promoted
to the transcendental world
to be one of the liberated associates
of the Lord
in the Kingdom of God.

[versified from the lectures of A.C. Bhaktivedanta Swami by his disciple Brahmananda Das Brahmachary]