Does the Shar’i (legal) evidence necessitate pronouncing the phrase once or twice, as in the Adhan?

Forms of the Iqamah (definition) (call to commence prayer) have been reported from the Prophet, peace and blessings be upon him, among them:

The first form (eleven phrases): "Allah is the greatest, Allah is the greatest. I bear witness that there is no god but Allah. I bear witness that Muhammad is the Messenger of Allah. Come to prayer, come to success. The prayer has begun, the prayer has begun. Allah is the greatest, Allah is the greatest. There is no god but Allah." Al-Albani authenticated the hadith (definition) indicating this form, and the majority of scholars preferred it.

The second form (seventeen phrases): In this form, the phrases of the Iqamah are doubled, except for the first Takbir (Allah is the greatest) and the Tawhid (definition) (declaration of oneness of God) at the end, and "Qad Qamat Al-Salah (definition)" (the prayer has begun) is repeated twice. Al-Albani authenticated the hadith indicating this form, and Imam Abu Hanifa preferred it.

Both forms are authentically reported from the Prophet, peace and blessings be upon him. Whoever performs either of them has acted in accordance with the Sunnah (definition). Sheikh Ibn Baz was asked about the permissibility of the Iqamah having the same number of phrases as the Adhan (definition), and he replied that it is permissible and a type of Sunnah, indicating that Bilal used to make the phrases of the Iqamah single, except for the phrase "Qad Qamat Al-Salah" and the Takbir. It is better for a Muslim not to restrict himself to one form, but rather to perform what has been authentically reported from the Prophet, peace and blessings be upon him, with variation, so as not to abandon the Sunnah.