It was narrated from Ibn ‘Abbas that the Prophet (ﷺ) said Takbir four times.
Explanation & Benefits
Maulana Ataullah Sajid
Benefit:
It is narrated in the hadiths regarding the funeral (janazah) takbirs that the number of takbirs ranges from three to nine, but there is consensus (ijma‘) of both the early and later generations (salaf and khalaf) on four takbirs, and most narrations are also concerning this number.
Furthermore, in Sahih al-Bukhari as well, only four takbirs for the funeral prayer are narrated.
And Allah knows best.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 1504