Чужой обед похваляй, да и сам ворота открывай

See В гости ходить, к себе водить (В)

Var.: По гостям гуляй, да и сам ворота отворяй

Cf: The best way to gain a friend is to be one (Am.). Friendship cannot always stand on one side (Br.). Friendship cannot stand all on one side (Am.). Не who would have friends must show himself friendly (Am.). One complimentary letter asks another (Br.). The way to have a friend is to be one (Br.)