The stillness of night comforts us.

Literal

Night [gen-の] stillness [subj-が] us [obj-を] comfort-[favor-てくれる].

慰めてくれる — the verb 慰める ('comfort, console') + ~てくれる marks the action as done for the subject's benefit. Using ~てくれる with an inanimate subject ('the night's stillness') is a slight personification — the stillness is treated as a kind benefactor.