What is meant by "that which is known of the religion by necessity," can it be enumerated, and does it differ with the changing of times?

What is meant by "that which is known by necessity from the religion" is what the generality of Muslims know from the religion without deep contemplation or reflection, such as the obligation of prayer, zakat, fasting, and Hajj, and the prohibition of adultery, disobedience to parents, injustice, intoxicants, pork, and murder. These matters cannot be confined to a specific number because they vary among individuals and environments. Ignorance of them may be excused for someone who is new to Islam or lives in a non-Muslim environment, unlike someone who lives in a Muslim environment.