Bhante Rathanasara shared a discourse from the Anguttara Nikaya (4.128) in which the Buddha said that with the manifestation of a Tathagata, the Supremely Enlightened One, given its extreme rarity, four astounding and amazing things become manifest. People usually (1) delight in attachment, (2) rejoice in conceit, (3) take delight in excitement, and (4) are immersed and enveloped in ignorance.
But when the Tathagata is teaching the Dhamma (1) about non-attachment, (2) for removing conceit, (3) that leads to peace, and (4) for the removal of ignorance, people wish to listen, and they want to understand and realise the Dhamma. Such is the astonishing and marvellous ability of the Fully Enlightened One! Thus, we see that the Buddha has two unique functions: to be self-awakened first, and then to awaken others from the sleep of ignorance by teaching the Dhamma.
Bhante Rathanasara further illuminates each of these four astounding aspects from the light of the Four Noble Truths, and also from the perspective of our grasping of the five aggregates. The sutta also compares the four marks of an ordinary human being with the four marks of an enlightened human being.