Who said this, where and why...

[Rochelle]

I have a few quotes that I need to know where they came from ...

He who breaks a thing to find out what it is, has left the path of wisdom.

But if you can only speak ill of those who showed you mercy, keep silent.

Few can foresee whither their road will lead them till they come to its end.

It is not our part to master all the tides of the world, but to do what is in us for the succour of those years wherein we are set, uprooting the evil in the fields we know, so that those who live after may have clean earth to till. What weather they shall have is not ours to rule.

Does anyone know who said any of these and where they can be found? Thanks!