Ye shall give thereof the Lord's heave offering to Aaron the priest. The Levites tithed the people, the priests tithed the Levites. At this time the other Israelites were nearly fifty times as numerous as the Levites, and therefore they would have been exceptionally well provided for.
It must be remembered, however, that the Levites would naturally increase faster than the rest, not being exposed to the same dangers; and still more that tithes are never paid at all fully or generally, even when of strict legal obligation.
A glance along the history of Israel after the conquest will satisfy us that at no time could the people at large be trusted to pay their tithes, unless it were during the ascendancy of the Maccabees, and afterwards under the influence of the Pharisees (cf.
Malachi 3:9, Malachi 3:10). The Levites, indeed, appear in the history of Israel as the reverse of an opulent or influential class. It was no doubt much easier for the sons of Aaron to obtain their tithes from the Levites; and as these were very numerous in proportion, and the tithes themselves were only a part of their revenues, the priests should have been, and in later times certainly were, sufficiently rich.
If they were devout they no doubt spent much on the service of the altar and of the sanctuary.