What are the conditions required for one who establishes the proof against a Muslim who has fallen into shirk (associating partners with Allah)?

The questioner : Are there conditions required of those who establish the proof against these servants?

The Shaykh : There is no doubt that it is obligatory for him to be a scholar. In reality, we know that many of our enthusiastic brothers fall into error. One of them may be someone who recently entered the da'wah (calling to Islam) and was part of that misguided public who were astray from the right path. Then Allah (Mighty and Majestic) guided him, and he praised and thanked Him. However, he did not become a scholar; he merely picked up the creed from some of the callers. Perhaps he does not even know how to read a verse as it was revealed. He meets with some shaykhs who, without doubt, have a general Islamic culture. As soon as this young Salafi says to him, "This is shirk, this is kufr (disbelief), and this is misguidance," he thinks that he has established the proof against him. No, the matter is not like that. It is not that easy. In truth, the one who should establish the proof against these shaykhs—so that his words have an impact and he deserves to be said to have established the proof against them—should be like them, if not more knowledgeable than they are, specifically regarding the tawhid (the oneness of Allah) he is calling them to and the avoidance of associating partners with Allah (Mighty and Majestic). The proof is not established by one who understands what Allah said and what the Messenger of Allah (peace and blessings be upon him) said, but by one who merely repeats from those who say, "Allah said so and so, and the Messenger of Allah said so and so." In short, it is obligatory for the one who establishes the proof to be a scholar, so that it becomes clear to the one being called that he has fallen under a clear command. Then either he believes, or he denies, as the Companions did, or as the Arabs did with the Messenger (peace be upon him). Those who were guided among the Companions, Allah increased them in guidance, and those who disbelieved, they were stubborn. And as He (the Exalted) said: This certainty is what constitutes disbelief. So who attains this certainty in the hearts of those far from guidance? It is the one who has knowledge of the Book and the Sunnah.