Do we humans need a mediator with Jesus? The Father is very scary in what He is—terrible spirit. So we are like Israelites were in Exodus, needing one like Moses to mediate between us and this God. Yet Jesus is painted by many as equally scary now he is risen immortal in heaven. But no, we can still find Jesus to be a relatable man we can interact with out and about: even though his interactions with Saul of Tarsus on the Damascus road were rather scary, it is something we can cope with in open air life more than we can cope with the Father, the almighty spirit who is utmost God. The Father is only one we can interact with if He deigns to keep to direct contact in say a dream, hiding from us the deadly peril of seeing Him out in the open like Moses did. The Holy Spirit is different again as one who might visit many at once in their lives or in a church service: Invisible but manifested in gifts and visions, although sometimes in some visible form like the dove or the tongues of fire.
