I was wondering, can a weak hadith be corroborated by Mawqoof (attributed to a Companion) narrations from the Companions? For example, what if they are about matters of the Unseen?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

First of all, we say that the authentic Mawqoof narrations about matters that are not subject to personal opinion and were reported from a Companion who was not known to relate from the Israelites take the ruling of Marfoo‘ narrations (those directly attributed to the Prophet ) as stated by the scholars of Hadeeth. Please, refer to fatwa 337342.

This kind of Mawqoof hadeeth strengthens the weak hadeeth.

Abdullah ibn Yoosuf Al-Jadee’ wrote a chapter about strengthening the weak hadeeth with the Mawqoof hadeeth in his book Tahreer ‘Uloom Al-Hadeeth. He concluded that the Mawqoof hadeeth does not strengthen the Marfoo‘ hadeeth except if it is about a matter wherein there is no room for personal opinion and provided it is not one of the Israelite narrations.

Allah knows best.