The Seal of the Hand

The Sanskrit word mudrā means a seal: the signet that stamps, and the impression it leaves. Monier-Williams records both senses, and a third: the name of "particular positions or intertwinings of the fingers", practised in worship and "supposed to possess an occult meaning and magical efficacy".

Greek has the exact word. A σφραγίς is a seal, a signet, the mark that makes a thing one's own. Theognis set his σφρηγίς upon his verses; the early Church called its rite of initiation the σφραγίς. A mudra is a seal pressed with the living body: the hand closes a circuit, marks an intention and stamps it on the soul.

ἡ ψυχὴ ὥσπερ ἡ χείρ ἐστιν· καὶ γὰρ ἡ χεὶρ ὄργανόν ἐστιν ὀργάνων.
"The soul is like the hand: for the hand is the instrument of instruments."Aristotle, On the Soul III.8, 432a1

Anaxagoras held that the human being is the wisest of animals because it has hands. Aristotle answered that it has hands because it is the wisest (Parts of Animals IV.10, 687a). Either way the hand stands at the meeting of intellect and matter. That's why every sacred tradition has given it a language.