Three gittin are void; but if she married, the offspring is legitimate: [if] he wrote [it] with his handwriting, but there are no witnesses on it; [if] there are witnesses on it, but it has no date; [if] it has a date, but it has only one witness. These three gittin are void; but if she married, the offspring is legitimate. R' Elazar says: Although there are no witnesses on it, but he gave it to her in the presence of witnesses, it is valid, and one collects from mortgaged properties, because witnesses sign on a document only for the sake of the general good.