Shabbos, Chapter 9, Mishnah 4. This mishnah is the last of the series in which a verse is brought to prove a halachah.
The words of the Mishnah:
"Minayin l'sichah shehi kishtiyah b'Yom haKippurim" - from where do we know that anointing with oil is forbidden on Yom Kippur just as drinking is forbidden?
"Af al pi she'ein re'ayah ladavar" - we have no full proof for this.
"Zecher ladavar" - nevertheless, there is an allusion to this idea.
"Shene'emar: Vatavo chamayim b'kirbo v'chashemen b'atzmosav" - the verse in Tehillim says: and it came like water inside him, and like oil into his bones.
From here Chazal understood that drinking water is to be compared to anointing with oil: just as drinking water is forbidden on Yom Kippur, so too anointing with oil is forbidden on that day.
To summarize: in this mishnah, which concludes the series of mishnayos that derive a halachah from a verse, we learned the source for the prohibition of anointing with oil on Yom Kippur: this is not a full proof but merely a "zecher ladavar," based on the comparison in the verse "Vatavo chamayim b'kirbo v'chashemen b'atzmosav" - which equates anointing with drinking.