Blind zeal can only do harm. [Ger., Blinder Eifer schadet nur.]

Blind zeal can only do harm.

Zealous men are ever displaying to you the strength of their belief, while judicious men are showing you the grounds of it.

But zeal moved thee; To please thy gods thou didst it!

But his zeal None seconded, as out of season judged, Or singular and rash.

I remember a passage in Goldsmith's "Vicar of Wakefield," which he was afterwards fool enough to expunge: "I do not love a man who is zealous for nothing."