New moon and sabbath, the calling of a convention​—I cannot put up with the use of uncanny power along with the solemn assembly. Your new moons and your festal seasons my soul has hated. To me they have become a burden; I have become tired of bearing them.” (Isaiah 1:13, 14) Grain offerings, incense, Sabbaths, and solemn assemblies are all part of God’s Law to Israel. As to “new moons,” the Law simply directs that these be observed, but wholesome traditions have gradually grown up around the observance. (Numbers 10:10; 28:11) The new moon is treated as a monthly sabbath, when the people would desist from work and even gather for instruction from the prophets and priests. (2 Kings 4:23; Ezekiel 46:3; Amos 8:5) Such observances are not wrong. The problem lies in doing them for mere show. Moreover, the Jews are resorting to “uncanny power,” spiritistic practices, right along with their formal observance of God’s Law.b