Is it permissible to perform only three Takbirat in the funeral prayer?

Primary text

It is not permissible to perform only three Takbirat in the funeral prayer. 'Abdullah ibn 'Abbas narrated that he performed three Takbirat, which did not please Abu 'Abdullah (Ahmad), who stated that Anas once performed three in forgetfulness and repeated the prayer. This deficiency is contrary to what was narrated from the Prophet (peace be upon him).