What is the ruling of the case of an Imaam who made five Takbeerahs in the funeral prayer instead of four?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

The majority of scholars among the Companions and their followers said that the funeral prayer consists of four Takbeerahs. It is the view of At-Thawri, Maalik, Ash-Shaaf‘i, Ahmad, Is-haaq and the people of opinion. Moreover, it was the last practice of the Messenger of Allaah, sallallaahu ‘alayhi wa sallam.

In Al-Istithkaar, Ibn Abd Al-Barr narrated that Abi Bakr Ibn Sulayman said that the Prophet, sallallaahu ‘alayhi wa sallam, would make four, five, seven or eight Takbeerahs until An-Najaashi died and then he, sallallaahu ‘alayhi wa sallam, lined the Companions up behind him and offered the funeral prayer with four Takbeerahs. He, sallallaahu ‘alayhi wa sallam, adhered to this tradition until he died. However, some scholars adopt the opinion that the funeral prayer consists of five Takbeerahs.

Nonetheless, if an Imaam made more than four Takbeerahs, he is to be followed despite the fact that he opposed the majority of the scholars. This is because of his saying, sallallaahu ‘alayhi wa sallam: “The Imaam is appointed so that he should be followed.”  [Abu Dawood]

Imaam Ahmad as well as Is-haaq said: “If the Imaam made four Takbeerahs, he must be followed”. However, the Maaliki scholars said “If the Imaam made more than four Takbeerahs in the funeral prayer, the people should cut the prayer by making Tasleem (i.e. salutation at the end of prayer) and not follow him, but the first opinion is the most preponderant one.

Allaah Knows best.