The Ratha-vinita Sutta (MN 24), The Relay of Chariots discourse, outlines the practice of the Dhamma from beginning to end using an analogy of a relay of chariots, or delivering the mail by the Pony Express.
Related Teaching from 2020
MN 24 Ratha-vinitha Sutta | The Relay of Chariots
https://youtu.be/Eo1kLbC65qE