This proverb teaches prudence on money.

If your father promises to give you 500 dollars on your twentieth birthday,
which is in six months time, don’t borrow money on the strength of it. It is
not that you do not trust your father to keep his promise, but anything may
happen in the meantime and you may be faced with a debt that you cannot repay.

The proverb is attributed to Thomas Jefferson the third president of US.

##### See also:

* Catch your bear before you sell its skin
* Don’t count your chickens before they are hatched
* Do not halloo till you are out of the wood
* First catch your hare
* There’s many a slip ‘twixt the cup and the lip