Is repeating the takbeer after the imam when going into ruku, sujood and so on, mandatory?

The majority of scholars hold the view that the takbīrāt al-intiqāl (the transitional takbīrs during prayer) are Sunnah. However, the Ḥanbalīs consider them to be among the wājibāt (obligatory acts) of the prayer. If the follower (ma’mūm) omits this takbīr, the imam suffices on his behalf.