The moving finger writes

What's the meaning of the phrase 'The moving finger writes'?

Whatever one does in one's life is one's own responsibility and cannot be changed.

What's the origin of the phrase 'The moving finger writes'?

This line originates in Edward Fitzgerald's translation of the poem The Rubáiyát of Omar Khayyam, 1859:

The Moving Finger writes; and, having writ,
Moves on: nor all thy Piety nor Wit
Shall lure it back to cancel half a Line,
Nor all thy Tears wash out a Word of it.