From the peculiar structure of the roofs of Eastern houses it can easily be seen how grass might there spring up and yet not have a flourishing growth. Dr. Robinson, speaking of the houses near Lebanon, says: “The flat roofs of the houses in this region are constructed by laying, first, large beams at intervals of several feet; then, rude joists; on which, again, are arranged small poles close together, or brush-wood; and upon this is spread earth or gravel rolled hard. This rolling is often repeated, especially after rain, for these roofs are apt to leak. For this purpose a roller of stone is kept ready for use on the roof of every house. Grass is often seen growing on these roofs” (Biblical Researches, vol. 3, p. 39).
The earth on the roof affords a starting place for the grass, but the frequent use of the roller and the trampling of feet give it but a poor chance for life. “It withereth afore it groweth up.” The same figure is also used in 2 Kings 19:2626Therefore their inhabitants were of small power, they were dismayed and confounded; they were as the grass of the field, and as the green herb, as the grass on the housetops, and as corn blasted before it be grown up. (2 Kings 19:26), and in Isaiah 37:2727Therefore their inhabitants were of small power, they were dismayed and confounded: they were as the grass of the field, and as the green herb, as the grass on the housetops, and as corn blasted before it be grown up. (Isaiah 37:27).
Travelers who have visited Persia tell us of houses the roofs of which are covered with green sod, from which the grass grows luxuriantly. Hay is said to be gathered from these roofs, and lambs are turned out on them to pasture. The same is reported of northern Gothic countries. The psalmist however, could not, as some think, have had such roofs in mind, even admitting that he ever saw them, since the application of the illustration pre-supposes grass, not of luxuriant growth, but short-lived.