I read the below references which says that righteous dead souls can benefit the living. hence supplicating to them is permissible.
Imam Razi wrote,
If a person went to the grave of someone with a strong soul, complete in essence, strong in influence, and stood there for a while, and was influenced by the soil there – the soil that the soul of the dead is attached to – then a mutual attachment occurs between these two souls due their gathering on that soil. They become like two polished mirrors reflecting each other’s rays; all that has been acquired in the visitor’s soul of proof-based knowledge, knowledge gained from effort, and high morals like submission to Aļļaah, and being content with what Aļļaah has predestined, reflects a light that travels to the soul of the dead hos
Imam Ibn Qayyim wrote: This soul has after the departure a whole other importance and other actions. In this regard dreams have been collaboratively mass narrated among human kind about the actions of souls after their death, actions they were not able to do while in their bodies, such as one, two or a few souls defeating entire armies and the like. Very many people have seen the Prophet with Abu Bakr and ˆUmar in their sleep having defeated the armies of kufr and injustice, and then their armies are overwhelmed and crushed despite large numbers, and the weakness and small numbers of the Muslims (Ar-Ruuĥ, P. 102-103).”[22
Can you please explain why major scholars mention that dead souls can benefit living. Was it the early Sunni belief?