77 Pesachim 9/1-4

(1) “[The Lord spoke to Moses, saying: Speak to the children of Israel, saying: If anyone of you or of your generations] Was unclean [by reason of contact with a dead body] or on a distant journey” (Numbers 9:9-10) And did not observe the first [Passover], [Then] he must observe the second [Passover]. [If] he [unintentionally] erred Or was prevented And did not observe the first [Passover], [Then] he must observe the second [Passover]. If so [asked the Mishnah], Why is it said (in Numbers 9:10): [That those] “unclean [by reason of contact with a dead body] or on a distant journey” [observe the second Passover]? [The Mishnah answers: It is to teach] that these [“unclean by reason of contact with a dead body or on a distant journey”] are exempt from being cut off from their kin, But those [who deliberately fail to observe the Passover] are liable to being cut off from their kin.

(2) What is “a distant journey” (within the meaning of Numbers 9:10)? From Modi’in and beyond, And the same distance in any direction [from Jerusalem is a distant journey] — [These are] the words of Rabbi Akiva. Rabbi Eliezer says: [A journey is distant anytime one leaves] from the threshold of the Temple Court and beyond. Said Rabbi Yose [to Rabbi Eliezer]: For that reason there is a dot over the letter hei [ in the word rechokah - “distant” - in Numbers 9:10], [In order] to teach: Not because it is really distant, But [when one has departed] from the threshold of the Temple Court and beyond [One is regarded as being on “a distant journey”].

(3) What is the difference between the first Passover and the second [Passover]? The first [Passover] is subject to the prohibition that “[Leaven] shall not be seen [with you]” (Exodus 13:7) And “[leaven] shall not be found [in your houses]” (Exodus 12:19); While at the second [Passover, One may have both] leavened and unleavened bread in the house. The first [Passover] requires [the reciting of] Hallel (Psalms 113–118) when [the Passover lamb] is eaten, While the second [Passover] does not require [the reciting of] Hallel when it is eaten. But both [first and second Passover] require [the reciting of] Hallel when they are offered, And they [both] are eaten roasted with unleavened bread and bitter herbs, And they [both] override the Sabbath.

(4) If a Pesach sacrifice is [permitted to be] brought in [a state] of impurity, zavim [males who have certain types of atypical genital discharges, which render them impure], zavot [females who have certain types of atypical genital discharges, distinct from their menses, which render them impure], niddot [women who have menstruated and are thereby impure] and women [rendered impure by virtue of] having given birth may not eat from it; but if they ate [from it], they are exepmt from karet‎. Rabbi Eliezer also exempts [them from karet if they] enter the Temple [in that state when the Pesach sacrifice is being brought in impurity].