Contradiction with Exodus 34:26
Unlike Numbers 15:21, which mandates the offering of dough's first part to God, Exodus 34:26 prescribes bringing the first of the firstfruits of the land to God's house.
Exodus 34:26: The first of the firstfruits of thy land thou shalt bring unto the house of the LORD thy God. Thou shalt not seethe a kid in his mother's milk.
Contradiction with Leviticus 23:17
This verse instructs to bring two wave loaves of two-tenth deals baked with leaven as firstfruits, while Numbers 15:21 specifically focuses on setting aside dough.
Leviticus 23:17: Ye shall bring out of your habitations two wave loaves of two tenth deals: they shall be of fine flour; they shall be baken with leaven; [they are] the firstfruits unto the LORD.
Contradiction with Deuteronomy 18:4
Instead of referring to dough specifically, this verse calls for giving firstfruits of grain, wine, and oil to the priests, showing a broader agricultural focus.
Deuteronomy 18:4: The firstfruit [also] of thy corn, of thy wine, and of thine oil, and the first of the fleece of thy sheep, shalt thou give him.
Contradiction with Proverbs 3:9
Proverbs 3:9 speaks about honoring the Lord with all possessions and the firstfruits of all increase, highlighting a broader requirement than just dough as in Numbers 15:21.
Proverbs 3:9: Honour the LORD with thy substance, and with the firstfruits of all thine increase: