Gam zu ltovah literally means This too is for the good, but it does not have a precise colloquial English equivalent. The closest is every cloud has a silver lining.

You usually say it in the face of some small or large setback. It might be spoken as an expression of faith; eg in exasperation you watch the train pull out of the station and, attempting to console yourself, mutter Gam zu ltovah. Alternatively, it could be said when you find some confirmation of your faith, for example on finding an old friend or a