What is the ruling on one who prays according to the custom of their country and refuses to learn about errors in their worship, relying on the fact that the mercy of Allah is vast?

A Muslim must learn the rulings of worship without which obligatory acts cannot be valid, such as the pillars and obligations of prayer. Otherwise, he would be sinful, and this is by the consensus of the scholars. So, whoever finds someone to inquire from about the obligations of his religion to act upon them, it is incumbent upon him to ask and learn. One must beware of surrendering to the whispers of Satan by arguing with the vastness of Allah's mercy to become lazy in learning the obligations. Allah has commanded His servants to combine fear and hope. Therefore, one should not be content with merely looking at Allah's mercy but should also include the fear that his deeds might not be accepted, striving to perform worship perfectly. Similarly, scholars and callers to Islam must clarify to people what they need regarding their religious matters.