‘Then Judah said to Tamar, his daughter-in-law, “Remain a widow in your father's house until Shelah my son is grown up”, (for he said, ‘Lest he also die like his brothers'). And Tamar went and lived in her father's house.'
Having lost two sons through premature death Judah is concerned for the safety of his third, who is also under obligation to raise up seed for his brother. But he is not yet of age for marriage. Thus he promises Tamar that as soon as he is (and it would not presumably be too long) he will carry out his duty with her.
“Remain a widow in your father” s house.' It was the custom among many that a widow returned to the protection of her parents, although it was not necessarily required (Ruth 1:8; Leviticus 22:13). But the thought is that she remain there only until she can marry Shelah. Judah is here telling her not to marry again until Shelah is of age. Thus he puts himself under even deeper obligation, and his future conduct is inexcusable.
“Lest he also die like his brothers.” It may be that Judah felt she was under some evil influence that had caused the death of his sons (compare the Jewish book Tob 3:7-17 in the Apocrypha for such an idea). Alternately he may simply have feared that if Shelah did not fulfil his duty to his brother's wife he also would die. But his later actions would not support this latter.
“And Tamar went and lived in her father” s house.' She was separated from the tribe and returned home where she could not be a danger.