A pure devotee always yearns to associate personally with the Lord and render service unto Him. The examples given in this regard are most appropriate. A small baby bird is practically never satisfied except when the mother bird comes to feed it, a small calf is not satisfied unless allowed to suck the milk from the mother's udder, and a chaste, devoted wife whose husband is away from home is never satisfied until she has the association of her beloved husband.

From Srila Prabhupada's purport to SB 6.11.26