。
Please take a bath.
Literal
Honorable-bath [obj-を] honorific-take [request-ください].
お召しください is the keigo (respectful) form of する/着る/食べる etc. — here お風呂をお召しになる means 'to take a bath' in highly elevated language. This is the kind of phrase a ryokan attendant or servant might use when inviting a guest to bathe. Extremely high register — almost archaic in modern usage.