JACK will ever make a Gentleman:

This Proverb teaches, that every one will not make a Gentleman, that is vulgarly called so, now-a days: There is more than the bare Name required, to the making him what he ought to be by Birth, Honour and Merit: For let a Man get never so much Money to but an Estate, he cannot purchase one Grain of GENTILITY with it, but will remain JACK in the Proverb still, without Learning, Virtue, and Wisdom, to enrich the Faculties of the Mind, to inhance the Glory of his Wealth, and to ennoble the Blood; for put him into what Circumstance you please, he will discover himself one Time or other, in Point of Behaviour, to be of a mean Extract, awkward, ungenteel, and ungenerous, a Gentleman at Second-hand only, or a vain-gloious Upstart: For you cannot make a silken Purse of a Sow's Ear; Ex quovis ligno Mercurius non fit, say the Latins.

Nathan Bailey, Dictionary of Proverbs 1721