It is one thing to have a ZEAL for God and another thing to have a SEAL from God

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.

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

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."