meaning of 從 in 必操几杖以從之
the verse in the book of rites (禮記), chapter 曲禮上:

謀於長者・必操几杖以從之

i would interpret it as:
[in situation of | if | when] seeking advice (謀) from (於) an elder (長者)・[one] must (必) hold (操) [readily] the “arm rest” &amp; staff (a strong stick or pole) (几杖 —&gt; 憑几 &amp; 手杖); for the purpose of (以) attending to (從之)
https://ctext.org/dictionary.pl?if=gb&amp;id=9489
so, “從之” refer back to the “elder” that one’s seeking advice from.
btw, an “arm rest” (憑几) is a tool, when people is sitting on a mat, on floor, for putting their arms on it for resting, something like this:


have fun :)