Halakhah zu Hoschea 8:10

And likewise from the laws of the commandment are matters from which the sages are exempted from the angle of their honor and awe - such as building and digging for the country and similar to them; and likewise taxes that the kings impose on the people of the land, whether it is a tax that is fixed on all of the people of the city together (as a lump sum) or whether it is fixed on each and every man or whether it is not fixed at all. They are exempt from all of this, as it is stated (Hoshea 8:10), "Though they have hired among the nations, now I will gather them, and they will begin to be diminished by reason of the burden of kings and princes" (which is understood regarding this in Bava Batra 8a, "If all learn [Torah], I will gather them already now; and if only a few, they will be excused from the burden imposed by kings and princes").