What is the meaning of the supplication: "O Allah, Lord of this perfect call and the prayer to be established"?

Whoever says after the Adhan: "O Allah, Lord of this perfect call and the نماز to be offered, grant Muhammad al-Wasilah and al-Fadilah, and raise him to the praised station which You promised him," will have the intercession of the Prophet, peace and blessings be upon him, on the Day of Resurrection. "This perfect call" refers to the call of Tawhid (monotheism), and "the نماز to be offered" refers to the prayer being called to. "Al-Wasilah" is a high station in Paradise specifically for the Prophet, and "al-Fadilah" is his elevated rank above all other creation. "The praised station" is the Grand Intercession on the Day of Resurrection, for which people will praise him.