Foul water slockens fire.

Frae saving comes having.

Frae the teeth forward.

He speaks from the lips only, not from the heart.

Freedom's a fair thing.

Fresh fish and poor friends soon grow ill-faur'd.

Fresh fish and unwelcome friends stink before they're three days auld.

Friday flit, short time sit.

Meaning that to remove on a Friday is unlucky.

Friday rules Sunday.