It seems your question is incomplete. If you're asking about a specific strict religious group or movement, please provide more context or clarify which tradition or period you're referring to. Examples could include the Puritans, the Amish, or various sects within major religions.
Hermit.
The Cistercians or Trappists are quite strict in their dedication to the cloistered monastic lifestyle.
It wasn't needed
Elizabeth was a strict protestant. She allowed some religious freedom but not much.
by being strict and moral, and sober and religious.
fundamentalism
Their Religious Rule Was Too Strict.
They had many gods and could choose one to worship.
no that is not a religious name
A government based upon strict religious rules is often referred to as a theocracy. In a theocracy, religious leaders typically hold political power, and laws are derived from religious texts and doctrines. This system can result in governance that prioritizes religious adherence over individual freedoms and secular principles. Examples include Iran's Islamic Republic and Vatican City's governance.
Puritans were strongly religious and strict. Quakers also lived there.
While bearing in mind that 'strict' is very much a relative term, and without overlooking the great variety of Muslim sects and practices, it can reasonably be said that, from the ordinary Western perspective, Muslims are 'strict' in respect to their moral values, their religious devotion, and their general comportment. The reason for this 'strictness' is cultural and religious alike, as the traditional home-cultures and religious authorities for Muslim practice and belief are far more traditional (or, conservative) and thus 'strict' than what generally can be found throughout the West in the 21st century.