For example, we think that Buddha Shakyamuni and Vajrasattva are two different deities. However, they are actually manifestations of the true nature of mind, or tathagatagarbha (buddha nature). This is like all kinds of images appearing on a screen even though they all come from one negative. The nature of mind is primordially pure. Any image projected from the pure tathagatagarbha is essentially one without any difference. In fact, Vajrasattva is also a manifestation of Buddha Shakyamuni.

[Excerpt from Luminous Wisdom Book Series ~ The Guru Yoga Practice of the Seven-Line Prayer to Padmasambhava]