Webster's Revised Unabridged Dictionary · 1913

Behest

Behest ({not transcribed}) , noun

[Old English biheste promise, command, Anglo-Saxon behas promise; pref. be- + has 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. [Obsolete]
The time is come that I should send it her, if I keep the behest that I have made. — Paston

Behest , transitive verb

To vow. [Obsolete] — Paston