Talmud for Pesachim 7:2
ר"מ אומר אוכלין כל חמש ושורפין בתחלת שש ר' יהודה אומר אוכלין כל ארבע ותולין כל חמש ושורפין בתחילת שש:
In standing up to recite the Prayer ('Amida), the feet must be met. There are two opinions on this subject, viz. that of R. Levi, and that of R. Shimon. The one says: it is to imitate the angels; the other says: it is to imitate the priests. The latter opinion is founded on the verse, " Neither shalt thou go up by steps to mine altar" (Exod. xx. 2); for the priests had to go to the altar by placing the toe beside the heel, and the heel beside the toe (i.e. by taking very little steps). The former opinion is based on the verse, " And their feet were straight feet" (Ezek. i. 7). Now, II. Hanina bar-Andira, in the name of R. Samuel bar-Zootai, says : The angels have no knee-joint, according to (Dan. vii. 16), " I came near unto one of them, that stood (always) by.'" R. Hoona says: If one sees the priests in the Synagogue at the time of their first blessing of the people, one must say: «' Bless the Lord, ye his angels" (Ps. ciii. 20); if at the second benediction: "Bless ye the Lord, all ye his hosts" (Ps. ciii. 21); if at the third benediction: "Bless the Lord, all his works" (Ps. ciii. 22). For the Prayer of Mousaph (additional)
Jerusalem Talmud Pesachim
Jerusalem Talmud Pesachim
The argument goes as follows: For any action up to the pouring of the blood, the wrong intent before or during the action disqualifies. But for actions required after the pouring of the blood, such as burning of the parts or eating the meat, a wrong intent before the pouring of the blood disqualifies, but a wrong intent at the moment of the action is irrelevant. Therefore, the rules of piggul cannot be used to infer rules for actions preceding the pouring of the blood.. If he slaughtered for its purpose in order to burn its parts not for its purpose, would that not be piggul? If he slaughtered for its purpose and in order to burn its parts not for its purpose, it is qualified.