Implementing objects as closures interpreting messages passed as parameters is exactly how many Scheme programmers (myself included) wrote "babby's first object system" in Scheme. Such an object system is also presented in SICP.
Finally we have the following Scheme Koan:
https://people.csail.mit.edu/gregs/ll1-discuss-archive-html/...
Amazing. I've heard both sayings before, but not the koan. Yet I somehow meditated upon it without knowing!