And it fell on a day. — Rather, And it came to pass at that time. Literally, during that day, referring to the period of the miracle just related. Perhaps, too, the contrast of the poor and rich woman is intentional.
Passed. — Crossed over — scil., the plain of Jezreel, which he would have to do, whether he went from Samaria, or from Carmel to Shunem, which lay on the slope of Little Hermon, about midway between the two.
A great woman — i.e., of high rank, or rich (1 Samuel 25:2; 2 Samuel 19:33). Rabbinic tradition identifies her with Abishag the Shunammite of 1 Kings 1:3 (!). In that case she must have been at this time more than 200 years old.
So it was. — It came to pass.
Passed by. — Crossed over, as above.
He turned in. — He would turn aside (frequentative). For the phrase, see Genesis 19:2.