Midrash sa Levitico 4:22: Sifra, Ein Yaakov (Glick Edition) & Ruth Rabbah

1) (Vayikra 4:22): "If (asher) a leader (nassi) sin ["asher," similar to "ashrei" ("fortunate")]: R. Yochanan b. Zakkai said: Fortunate is the generation whose nassi brings a sin-offering for his unwitting sin. If he brings a sin-offering for his unwitting sin, how much more so (is he contrite over) his deliberate sin. And if his nassi brings a sin-offering, how much more so is he (the common man) moved to bring a sin-offering (for his sin)! "a nassi": I might think the nassi of a tribe, like Nachshon; it is, therefore, written: "And he do one of all the mitzvoth of the L–rd his G d," and, elsewhere, (in respect to a king) (Devarim 17:19): "so that he may learn to fear the L–rd his G d." Just as there, the nassi is one who has no one above him but the L–rd his G d, so, here. (Scripture speaks of) a nassi who has no one over him but the L–rd his G d (i.e., a king).

(Fol. 9) R. Jeremiah used to say concerning the passage (Lev. 5, 5) And if his means be not sufficient, and again there is a passage (Ib. ib. 7) If he can not afford; all this speaks of persons that might become either poor or rich, which is not the case with either the High-priest or the priest anointed as the chaplain of the army; for concerning the latter, the passage says (Ib. 4, 22) Of all the things which the Lord his God, which signifies him who has for his superior, only his God; and concerning the High-priest, the passage says (Ib. 21, 10) And the priest that is highest among his brethren; i.e., he shall be highest in beauty, in might, in wisdom and in wealth. Acherim says: "Whence is it inferred that if he (the priest) is not rich, his people should make him so? The passage says highest among his brethren, i.e., he should be made great by his own brethren."

2) Why "(If) a nassi shall sin" (instead of "sinned")? For otherwise I might think that he must bring (a he-goat) for (unwitting transgressions committed) prior to his appointment. But (why the exclusion clause?) Is it not a kal vachomer (that he should not bring a he-goat?), viz.: If the high-priest, who brings his sin-offering (a bullock) for (unwitting sins committed) after removal from office, does not bring (a bullock) for (unwitting sins committed) prior to his appointment — a nassi, who does not bring his sin-offering (a he-goat) for (sins committed) after removal from office, how much more so should he not bring it for (sins committed) prior to his appointment! — No, this may be so with the high-priest, who does not bring (his sin-offering, a bullock,) for deed-unwittingness (alone, but only as a result of ruling mistakenly for himself), as opposed to a nassi, who does bring (his sin-offering, a he-goat,) for deed-unwittingness (alone). And since he does, I would think that he brings (a he-goat, too,) for prior sins; it is, therefore, written (to negate this): ("If a nassi) shall sin," after he is appointed; but he does not bring it for those sins which he committed as a lay person.