The word(s) "observeth" appears 2 time(s) in 2 verse(s) in Quran in Muhammad Pickthal translation.

(1) It is not righteousness that ye turn your faces to the East and the West; but righteous is he who believeth in Allah and the Last Day and the angels and the Scripture and the prophets; and giveth wealth, for love of Him, to kinsfolk and to orphans and the needy and the wayfarer and to those who ask, and to set slaves free; and observeth proper worship and payeth the poor-due. And those who keep their treaty when they make one, and the patient in tribulation and adversity and time of stress. Such are they who are sincere. Such are the Allah-fearing.

(2) He only shall tend Allah's sanctuaries who believeth in Allah and the Last Day and observeth proper worship and payeth the poor-due and feareth none save Allah. For such (only) is it possible that they can be of the rightly guided.