Majjima Nikaya … Which Sutta…??
Usually you can search using the pali text society number to find the right sutta, but the search doesn’t seem to be working right now.
Alternatively you can go to https://suttacentral.net/mn and scroll down to the right sutta.
You will notice that MN 60 begins at MN i 400, and MN 61 begins at MN i 414, so "M.I,401 " (MN i 401) is right at the beginning of MN 60.
Note the form of the reference you’re using:
- M is for “Majjhima”. We use “MN” for “Majjhima Nikaya”, in order to distinguish it from “MA”, the Madhyama Agama (which is the version in Chinese). The same applies for the other nikayas.
- I or i is the volume number. Normally in Buddhist studies this refers to the printed edition of the Pali text as published by the Pali Text Society. To me it is crazy to keep references linked to a single printed edition. So on SC our basic references are to the sutta number, which is constant throughout all editions. However, we supply the vol/page reference also, as Qianxi has kindly explained.
- 401 is the page number of the same printed edition.