God bless you

Meanings

1. May God bless you; said as a short prayer, benediction, or valediction for the recipient; usually religiously; sometimes nonliterally but rhetorically or culturally.
2. Said to somebody who has sneezed, as a rhetorical response; alternative form of bless you.

Etymology

From Middle English God blesse you, God blisse you. A clause in the present subjunctive inherited intact from a time when English was freely productive of it. Diachronically it is not a shortening; synchronically it is often surface-analyzed as such; present-day English has a heavy need for the modal auxiliary (may) to ensure syntactic clarity, whereas earlier English could more easily drop it.