"Muhammad ibn 'Abdullah": Is it a clarifying apposition or a substitute?

The Shaykh : Are you asking?

The questioner : Muhammad ibn 'Abdullah, the "ibn": Is it a clarifying apposition or a substitute?

The Shaykh : It is permissible for it to be a substitute and permissible for it to be a clarifying apposition, because "Muhammad" is ambiguous: Muhammad, the son of whom? When "ibn 'Abdullah" comes, it removes this ambiguity, so it becomes a clarifying apposition. It is also valid for it to be a substitute, because you intend to specify his lineage to his father only.