What is the ruling of Islam on one who is ignorant of the important and necessary Sharia rulings related to worship?

The scholars have stated that it is obligatory for a Muslim to learn the matters of religion that rectify his belief, worship, and dealings. Whoever fails to do so incurs sin due to his negligence. This is an individual obligation, as the Prophet, peace and blessings be upon him, said: "Seeking knowledge is an obligation upon every Muslim." Thus, a Muslim who is negligent in learning what is obligatory for him regarding the matters of his religion is considered disobedient.