A stone is heavy, and sand is weighty, but a fool’s provocation is heavier than both.
These two verses show the intolerable mischief, 1. Of ungoverned passion. The wrath of a fool, who when he is provoked cares not what he says and does, is more grievous than a great stone or a load of sand. It lies heavily upon himself. Those who have no command of their passions do themselves even sink under the load of them.
Commenting on Proverbs 27:3-4
A stone is heavy, and the sand weighty,.... As was the stone which was at the well's mouth, where Laban's flocks were watered, which could not be rolled away till all the shepherds were gathered together, Gen 29:2; and like the burdensome stone Jerusalem is compared to Zac 12:3; and as that at the sepulchre of Christ, rolled away by the angel, Mat 28:2.
heavy--The literal sense of "heavy," applied to material subjects, illustrates its figurative, "grievous," applied to moral. a fool's wrath--is unreasonable and excessive.