One who enters a town utters two prayers, one upon entering and one upon leaving. Ben Azzai says: Four, two upon entering and two upon leaving. [When he is about to enter he says: "…that You lead me into this town in peace." Once he has entered, he says: "I give You thanks for having led me into this town in peace" — two upon entering. When he is about to leave, he says: "…that You lead me from this town in peace." Once he has left, he says: "I give You thanks for having led me from this town in peace."] And he gives thanks for the past and cries out for the future. [Why all this? For one must give thanks to his Creator for the good that he has experienced and he must pray for good in the future.]
Mishnah Avodah Zarah
If [a Jew] left his wine in a wagon or on a ship while he went along a short cut, entered a town and bathed, it is permitted. But if [the Jew] informed him that he was going away [and he was absent a length of time] sufficient for the other to bore a hole [in a jar], stop it up and [the sealing clay] to become dry, [the wine is prohibited]. Rabban Shimon ben Gamaliel says: [a length of time] sufficient for him to open a cask, put a new stopper on and [the new stopper] to become dry. If [a Jew] left a non-Jew in his shop, although he kept going in and out, [the wine there] is permitted. But if [the Jew] informed him that he was going away [and he was absent a length of time] sufficient for the other to bore a hole [in a jar], stop it up and [the sealing clay] to become dry, [the wine is prohibited]. Rabban Shimon ben Gamaliel says: [a length of time] sufficient for him to open a cask, put a new stopper on and [the new stopper] to become dry.