Webster’s Revised Unabridged Dictionary · 1913
Behest
Be·hest′ (bē·hĕst′), n. [OE. biheste promise, command, AS. behǣs promise; pref. be- + hǣs command. See Hest, Hight.] 1. That which is willed or ordered; a command; a mandate; an injunction.
To do his master's high behest. Sir W. Scott.
2. A vow; a promise. [Obs.]
The time is come that I should send it her, if I keep the behest that I have made. Paston.
Be·hest′, v. t. To vow. [Obs.] Paston.