Gelug
Tsongkhapa was a big promoter of the Kadampa (Bka'-gdams-pa) teachings and the mahāyāna principle of universal compassion as the fundamental spiritual orientation. He combined this with a strong emphasis on the cultivation of in-depth insight into the doctrine of emptiness as taught by the Indian masters Nāgārjuna (2nd century) and Candrakīrti (7th century). Tsongkhapa said that these two aspects of the spiritual path, compassion and insight into wisdom, must be rooted in a big wish for liberation driven by a genuine sense of renunciation. He called these the "Three Principal Aspects of the Path", and said that it is on the basis of these three that one must embark on the profound path of vajrayāna Buddhism.