[If] one became tamei in the Courtyard, and the tumah escaped his memory, though he remembered the Temple; [or, the fact that it was] the Temple escaped his memory, though he remembered the tumah; [or] both escaped his memory, and he prostrated himself, or stayed long enough to prostrate himself, [or if] he went out by a longer way —- he is liable; by the shortest way —- he is exempt. This is the positive commandment concerning the Temple, for which there is no liability.

Now what is the positive commandment concerning the menstruant, for which there is liability? [If] one was cohabiting with a woman who was tahor, and she said to him, “I have become tamei,” and he withdrew immediately —- he is liable, because his exit is as pleasurable to him as his entry.

R' Eliezer says: A sheretz . . . and it escaped his awareness (Lev. 5:2) —- he is liable for forgetting the sheretz, but he is not liable for forgetting the Temple. R' Akiva says: And it escaped his awareness, and he was tamei (ibid.) —- he is liable for forgetting the tumah, but he is not liable for forgetting the Temple. R' Yishmael says: [The words] And it escaped his awareness, and it escaped his awareness (Lev. 5:23) [are stated] twice —- to make [one] liable both for forgetting the tumah and for forgetting the Temple.