What is the ruling of Islamic law regarding the obligation to correct erroneous religious information that has been conveyed to friends, and is failure to correct it considered concealing knowledge?

Whoever conceals knowledge that people need, without a valid excuse, has committed a grave sin. Among the most crucial areas of need is the correction of errors, which is part of the obligatory advice (naseeha) and fulfilling a trust (amanah). It is important to be aware of the danger of issuing a fatwa (religious ruling) without knowledge. Whoever issues a fatwa without knowledge must repent and seek forgiveness, and clarify the correct ruling to those who heard his error.