וְאִם־לֹ֨א תִמְצָ֣א יָדָהּ֮ דֵּ֣י שֶׂה֒ וְלָקְחָ֣ה שְׁתֵּֽי־תֹרִ֗ים א֤וֹ שְׁנֵי֙ בְּנֵ֣י יוֹנָ֔ה אֶחָ֥ד לְעֹלָ֖ה וְאֶחָ֣ד לְחַטָּ֑את וְכִפֶּ֥ר עָלֶ֛יהָ הַכֹּהֵ֖ן וְטָהֵֽרָה׃ (פ)
E se as suas posses não permitirem um cordeiro, então ela tomará duas rolinhas ou dois pombinhos, um como oferta queimada e um como oferta pelo pecado; e o Cohen fará expiação por ela, e ela será pura." {פ}
Guide for the Perplexed
The Levites did not sacrifice; they were not considered as being agents in the atonement of sins, for it was only the priest who was commanded “to make atonement for him” (Lev. 4:26) and “to make atonement for her” (Lev. 12:8). The duty of the Levites was the performance of vocal music; and a Levite became therefore disabled for service when he lost his voice. The object of the singing is to produce certain emotions; this object can only be attained by pleasing sounds and melodies accompanied by music, as was always the case in the Temple.