John Gills Exposition of the Bible Commentary - Proverbs 20:21
An inheritance may be gotten hastily at the beginning ,.... Of a man's setting out in the world in trade and business; and which sometimes is got lawfully, and this must be excepted from this proverb; but generally what is got hastily and in a short time is got unlawfully, and so does not prosper. Some Jewish interpreters, as Gersom, understand it of an inheritance which comes to persons from their friends, without any labour or industry of theirs; and which they are not careful to keep,... read more
Matthew Henry's Complete Commentary - Proverbs 20:21
Note, 1. It is possible that an estate may be suddenly raised. There are those that will be rich, by right or wrong, who make no conscience of what they say or do if they can but get money by it, who, when it is in their power, will cheat their own father, and who sordidly spare and hoard up what they get, grudging themselves and their families food convenient and thinking all lost but what they buy land with or put out to interest. By such ways as these a man may grow rich, may grow very... read more