Genesis 15:17

Now it came to pass that the sun had set: Heb. וַיְהִי הַשֶּׁמֶשׁ בָּאָה. [The subject apparently does not agree with the predicate, because שֶׁמֶשׁ is a feminine noun, whereas וַיְהִי is a masculine verb. Therefore, Rashi explains as follows:] This is similar to (below 42:35): “And it came to pass that they were emptying their sacks”; (II Kings 13:21): “And it came to pass that they were burying a man”; meaning: this event took place. [The subject of וַיְהִי is not הַשֶּׁמֶשׁ but דָבָר זֶה (i.e., it is as if the masculine noun דָבָר זֶה (this event) were inserted after וַיְהִי.] The same is true in the two instances quoted by Rashi, in which the subject is plural, whereas the predicate is singular. There too, the subject of וַיְהִי is דָבָר זֶה.]

the sun had set: Heb. בָּאָה. It had set.

and it was dark: The day darkened.

and behold, a smoldering furnace, etc.: He hinted to him that the kingdoms of the pagans would fall into hell. — [from Pirkei d’Rabbi Eliezer, ch. 28]

had set: Heb. בָּאָה Its accent is on the first syllable. Therefore, it is explained that it had already set; but if its accent were at the end, on the “alef,” it would be explained to mean: as it was setting. but it is impossible to say this, for it is already written (above verse 12): “Now the sun was setting,” and the passing of the smoking furnace happened after this. It is found that it had already set. And this difference exists in every word in the feminine gender, whose radical consists of two letters, such as בא (to come), קם (to arise), שב (to return). When the accent is on the first syllable, it is in the past tense, e.g., this case and e.g., (below 29:9): “and Rachel came (בָּאָה)”; (below 37:7): “my sheaf arose (קָמָה)”; (Ruth 1:15): “Lo! Your sister-in-law has returned (שָׁבָה).” However, when the accent is on the final syllable, it is in the present tense, denoting a thing that is happening now and is continuing to happen, like (below 29:6): “She is coming בָּאָה with the flocks”; (Esther 2:14): “In the evening she would come (בָּאָה), and in the morning she would return (שָׁבָה).”

And when the sun had set there was darkness. And, behold, Abram saw Gehinnam ascending, smoke with flaming coals and burning flakes of fire, werewith the wicked are to be judged. And, behold, He passed between those divisions.

AND BEHOLD, A SMOKING FURNACE, AND A FLAMING TORCH. It appeared to Abraham as if the furnace was all smoke and in its midst a flaming torch was burning, similar to a great smoke, with a fire flashing up. The “smoke” mentioned here is the cloud, and thick darkness mentioned at the giving of the Torah, and “the flaming torch” in its midst is “the fire” mentioned there: And thou didst hear His words out of the midst of the fire;, Verse 36. and it is further written: And the appearance of the glory of the Eternal was like devouring fire, etc. Thus the Divine Glory passed between the parts of the sacrifices, and this is the covenant which He made with Abraham forever. This is the meaning of the verse, the Eternal made a covenant with Abraham, as the Holy One, blessed be He, Himself carried through “the covenant of between the parts.” The student versed in the mysteries of the Torah will understand.

ויהי השמש באה, the word באה is accented on the first syllable, seeing that here it is a verb in the past tense.

ועלטה, a form of intense darkness. G'd hinted by the use of this intense darkness that there would be other exiles, and that the redemption from the exile in Egypt would not be the final redemption of the Jewish people. The description of the sun having set followed by עלטה, implies that there would be no light at all, no moon and no stars would be visible in the sky.

והנה תנור עשן ולפיד אשת, the word עשן is an adjective used in the same kind of meter as חכם סכל, which means חכם וסכל, "a wise man who acts foolishly." We would translate it here as "a smoking furnace." The point is that within the overall vision, Avram saw another furnace belching smoke, within the general atmosphere of intense darkness. This latter picture was an allusion to G'd's anger which coats Israel with its some during the long years of exile, the final exile which is the worst of them all. This is also what David had to say concerning this long and most difficult exile, when he exclaimed in Psalms 80,5 עד מתי עשנת בתפלת עמך, "for how long will You remain smoking angrily at the prayers of Your people?"