The self serene, fearless, firm in the vow of the Brahmachâri, the mind controlled, thinking on Me, harmonised, let him sit aspiring after Me.
In plain words: Krishna says the meditator should be calm and unafraid, and keep the vow of a brahmachari (a student who lives a pure, celibate life). With the mind controlled, he should sit thinking of Krishna and longing for Him.