And whence is it derived that the Torah scroll was given unconditionally? From (Devarim 33:4) "The Torah which Moses commanded us is the (eternal) inheritance of the congregation of Jacob." Whence is it derived that the covenant with Aaron was made unconditionally? From (Numbers 18:19) "It is a covenant of salt forever," (Ibid. 25:13) "And it shall be unto him and to his seed after him a covenant of eternal priesthood."