Numbers 9:13

9:13 But the man who is ceremonially clean, and was not on a journey, and fails to keep the Passover, that person must be cut off from his people. Because he did not bring the Lord’s offering at its appointed time, that man must bear his sin.

Numbers 33:55

33:55 But if you do not drive out the inhabitants of the land before you, then those whom you allow to remain will be irritants in your eyes and thorns in your side, and will cause you trouble in the land where you will be living.