Eruvin 4:4 - 4:5

מי שישב בדרך – [he had sat on the road] to rest and did not know that he was at the [Sabbath] limit of the city and it became dark for him there and when he stood up he saw that he was near to the city and to its [Sabbath] limit.

לא יכנס – [he should not enter] into the city to be like the people of the city, but rather from the place where it had become dark for him, he should measure two thousand cubits and on the place where they were able, he should go and no further.

ר"י אומר יכנס – [he should enter] and walk through the city and outside of it two thousand cubits like the people of the city, and the Halakha is according to Rabbi Yehudah.

בלא מתכוין – for he did not know that it had become dark for him when he was in the [Sabbath] limit of the city and he did not intend to make his Shabbat in the city but rather in his place.

יש לו אלפים אמה לכל רוח – for Rabbi Yohanan ben Nuri holds that ownerless things which lack the knowledge of its owners acquire their appointed place of Sabbath movements in their place and they have two thousand cubits in every direction and a person who sleeps who has no knowledge at the time when he acquires his appointed place of Sabbath movements, his law is like ownerless things and he has two thousand cubits in all directions, but the Rabbis hold that ownerless objects do not acquire their appointed place of Sabbath movements in their place but he who acquires title to them brings them to the place where he is able to go. Similarly, a person sleeping does not acquire his appointed place of Sabbath movement and he has nothing other than four cubits [of movement] alone. But the Halakha is according to Rabbi Yohanan ben Nuri for the person who is sleeping acquires his appointed place of Sabbath movements in his place and he has two thousand cubits in all directions but regarding ownerless property, the Halakha is according to the Sages for they are like the feet of all people and they do not acquire their appointed place of Sabbath movements in their place but the person who acquires them walks them to a place where he is able to go.

וחכמים אומרים אין לו אלא ד' אמות – since at the time that he sanctified the [Sabbath] day, he did not acquire his appointed place of Sabbath movements and he only has four cubits that the Torah provided him, as it is written (Exodus 16:29): “Let everyone remain where he is,” and the height of each average individual is three cubits and one [additional] cubit to stretch his hands and his feet.

ר' אליעזר אומר והוא באמצען – The Sages hold that we give him four cubits in each direction but Rabbi Eliezer states we give him four cubits which is two cubits to each side of him.

לאיזה רוח שירצה – he takes four cubits and after ascertaining one side, he cannot go back and ascertain another side.