expression to encourage :
2: You can take a horse to the water but you cannot make it drink.
said to mean that:
3: You can take the boy out of the country but you can't take the country out of the boy.
4: You can't tell a book by its cover.
5: You cannot catch old birds with chaff.
6: You cannot eat your cake and have it.
7: You cannot get blood from a stone.
8: You cannot judge a tree by its bark.
9: You cannot make bricks without straw.
10: You cannot teach old dogs new tricks.
used to say that:
11: You cannot wash charcoal white.