Luke 1:56

And Mary abode with her about three months ,.... That is, she continued with Elisabeth, as the Syriac and Persic versions express, about the space of three months; in which time, she had full satisfaction of the truth of the sign the angel had given her; namely, of Elisabeth's conception and pregnancy, for by this time she was ready to give birth; and she must now be fully assured, that she was with child herself: this space of three months is a term of time fixed by the Jewish doctors, to know whether a woman is with child or not, as in case of divorce or death: the rule runs thus F11 Maimon. Hilch. Gerushin, c. 11. sect. 18. Vid. T. Bab. Becorot, fol. 47. 1. ,

"every woman that is divorced, or becomes a widow, lo! she may not marry, nor be betrothed, until she waits, תשעים יום , ninety days (i.e. three months), exclusive of the day in which she is divorced, or her husband dies, and of the day in which she is betrothed; that so it may be known whether she is with child or not, in order to distinguish between the seed of the former, and the seed of the second husband.

And so in the case of marrying the wife of a brother, that died without issue F12 Misn. Yebamot, c. 4. sect. 10. T. Hieros, Yebamot, fol. 6. 1. T. Bab. ib. fol. 34. 2. & 35. 1. Maimon. Hilch. Yebum, c. 1. sect 19. T. Bab. Erubin, fol. 47. 1. , and of newly married couples mistaking their spouses F13 Misn. Yebamot, c. 3. sect. 10. :

and returned to her own house ; at Nazareth, in Galilee; and now it was, that Joseph, to whom she was betrothed, perceived she was with child; and suspecting evil, had a mind to put her away privately; but was informed by an angel of God, in a dream, of the whole matter; and was advised and encouraged to take her to wife, which he accordingly did; see Matthew 1:18 .