(Bamidbar 28:15) "And one kid of goats as a sin-offering to the L-rd": to atone for "a grave of the depth" (i.e., tumah which was discovered only after one had come in contact with it.) "in addition to the continual burnt-offering shall it be offered and its libation.": We are hereby apprised that the mussafim (of Rosh Chodesh) are sacrificed only between (the two temidim).
(Bamidbar 28:16) "And in the first month, on the fourteenth day of the month, it is Pesach to the L-rd": Scripture (here) makes it mandatory (and not optional.) (Ibid. 28:17) "for seven days matzoth shall be eaten": I might think that any matzoth (may be eaten [e.g., even those made of rice]). It is, therefore, written (Devarim 16:3) "You shall not eat chametz with it. Seven days shall you eat matzoth with it." Only that which can be matzah (unleavened) or chametz (leavened) (is forbidden in the leavened state). These are the five varieties: wheat, barley, spelt, rye, or oats. This excludes rice, millet, sesame, paragim, which never become matzah or chametz, but only decay.