You can lead a horse to water, but you can’t make it drink.
~ English proverb
Meaning:
You can give someone the opportunity to learn or to do something, but you can never force him to accept that opportunity.
It appears to be the oldest English proverb that is still in regular use today. It was recorded as early as 1175 in Old English Homilies: “Hwa is thet mei thet hors wettrien the him self nule drinken.”