While most Yiddish words derive either from Hebrew or German, with some others from the Slavic languages, bensch (or bentshn in the infinitive) is one the few to derive from Latin, and perhaps therefore one of the earliest Yiddish words.
The Yiddish scholar Max Weinreich wrote that Jews came to Germany from two main areas - France and Italy. Each group of immigrants brought words of their own. From Old French we get what Weinreich calls "western laaz" and from Old Italian "southern laaz". And so, bensch derives from the Old Italian benedicere (or benedictere), meaning "to bless". German also borrowed from the same Latin root for their word benedeien.
The English word "benediction" also derives from the same Latin root:
1432, from L. benedictionem (nom. benedictio), noun of action from benedicere "to speak well of, bless," from bene "well" + dicere "to speak"
Interestingly, the word eulogy has a similar etymology, although via Greek, not Latin:
from Gk. eulogia "praise," from eu- "well" + -logia "speaking"
So looking back at yesterday's post, the word bensch seems to fit a blessing from man to God, for those who understand it as meaning "praise".