Protestants say that a tithe of 10% of gross income is obligatory according to Scripture. Are Catholics bound to keep this rule?

The obligation of offering a tenth part of the produce as an offering to God and to His ministers is one of the legal prescriptions of the Mosaic law (Dt. 14:22) that Our Lord did away with when He came to fulfill the law in His own person. It is certainly true that under the new law, as under the old, the faithful owe support to the ministers of the altar. However, since the new law is interior, it is left to the generosity of the faithful in the practice of the virtues of justice and charity to determine the quantity. In fact, the Church has declared that support is strictly owed in justice to the ministers of the Church, and that it is not pure alms that can be withdrawn at will. The contrary opinion was one of the errors of John Wycliffe condemned at the Council of Constance in 1415 (Dz, 598). This is indeed a part of the natural law, that requires that those who minister receive a commensurate remuneration. It is also according to the divine law, as taught by Our Lord, "for the ...  more