If a gentile lit a lamp, a Jew may use its light; but if [he did so] for a Jew, he may not [use it]. If [a gentile] drew water to water his own animal, a Jew may water [his animal] after him; but if [he did so] for a Jew, he may not [use it]. If a gentile made a gangway upon which to disembark, a Jew may disembark after him; but if [he did so] for a Jew, he may not [use it]. It once happened that Rabban Gamliel and the elders were arriving on a ship, and a gentile made a gangway by which to disembark, and Rabban Gamliel and the elders disembarked by it.