"Thus, it is contradictory to propound that you should not train in the scriptural collections of the Hinayana because you are a Mahayana practitioner.

There are shared and unshared paths to enter the Mahayana. Since the shared are those things that come from the scriptural collections of the Hinayana, how could they be something to set aside?

Therefore, Mahayana followers must practice all those things taught in the Hinayana scriptural collections, with only a few exceptions, such as diligently seeking a blissful peace for oneself alone. This is the reason for extensively teaching all three vehicles in the very vast scriptural collections of the bodhisattvas."

Je Tsongkhapa