In 1971 the venerable Ecumenical Patriarch Athenagoras called John Zizioulas. He announced to him his intention to propose to the Holy Synod of the Ecumenical Patriarchate his election as hierarch of the Ecumenical Throne. Despite the extraordinary honor of this invitation and his childhood inclination towards the priesthood, considering the magnitude of the responsibilities and his desire to continue his academic and scientific work for some more time, Zizioulas begged the Patriarch to postpone this matter. Patriarch Athenagoras fell asleep the following year (1972), and it seemed for the moment that the question of the election of Zizioulas had ceased to exist. However, the successor of Athenagoras, venerable Patriarch Demetrios, with a patriarchal letter in the year 1974, invited Zizioulas to the Patriarchate for consultations in order for the Patriarchate to proceed with the “immediate elevation of [him] to the office of patriarch” following an already adopted Synod decision. Even though the matter was almost “done,” Zizioulas again asked the Patriarch to postpone the realization of this significant step in his life. In 1980, the late Metropolitan of Chalcedon, Meliton, called him on behalf of the Patriarch and brought up the issue in the form of the immediate promotion of Zizioulas as acting Metropolitan of the Ecumenical Patriarchate, which would entail his resignation from his university position in Glasgow. But even then, he hesitated to accept and asked for another postponement.

In 1968, after the illness and substantial abstinence from active service of Metropolitan of Chalcedon Meliton, the late hierarch Metropolitan Maximos of Sardes invited Zizioulas on behalf of Patriarch Demetrios and in the presence of the Metropolitans Chrysostomos of Myra and Bartholomew of Philadelphia (later Ecumenical Patriarch), the issue of the election of Zizioulas as hierarch of the Ecumenical Throne was raised again. Realizing now that his age did not permit a new postponement of the matter and obeying the numerous calls of the Church as the voice of God, he accepted his entry into the ranks of the holy clergy of the Great Church of Christ. He only asked to continue in parallel with his ecclesiastical and academic activities, at least for some time, which was accepted.