It is related from the blessed Hudhayfa that:
The Prophethood (nubuwwa) will remain among you for so long as Allah chooses, and He will remove it when He so wills. And a "Powerful Kingdom" will come and persist for so long as Allah desires. Then when He wills to eliminate it He will do so. Then there will come a despotic regime. And then a "caliphate based on the path of prophethood." Ramuz Al Ahadith, 1/257 (Abu Dawud "atTayalisi" - from Ahmad ibn Hanbal's "Musnad")
'Isa (as) and the Mahdi will come from the first path. The first path is qurb al-Nubuwwa. There is no intercession there. Whoever arrives by that path, there is no obstacle or intermediary between them. They take their abundance and bounty with no intercession from anyone. Because obstacles and intermediaries lie only on the other path. This way is different to the other.
Letters of Rabbani, Letter 534, 2/763-764
Question: How can this be said of a mujaddid (renovator of the faith)? Because the Prophet 'Isa (as) will descend from the sky and will be a renovator. The blessed Mahdi will appear and be a renovator. They will receive their bounty and abundance with nobody acting as intermediary. Because obstacle and intermediaries lie only on the other path. This way is different to the other.
Answer: Being an intermediary for abundance lies only on the second of the paths revealed above. On the first path, (that known as qurb al-nubuwwa), bounty and salvation do not come through any intermediary. The one who rises up in this path is by way of no intermediary or intercession. One attains bounty and abundance with no intermediary or intercession. Being an instrument and intermediary lies on the second path. These two paths must not be confused. The Prophet 'Isa (as) and the blessed Mahdi will arrive by the path of qurb al-Nubuwwa. The two sheikhs, Abu Bakr and the blessed Omar (ra) achieved this by the path of prophethood. They are under the protection of the Messenger of Allah (saas). Great is their glory. (Eternal Happiness, H.Hilmi Isik, 836 [Letter 123 of the Letters of Rabbani])