Commentary for Berakhot 4:5

On account of his poverty, he cannot afford artificial light ; therefore he takes his evening meal while there is yet sufiScient light. See fol. 3 a (p. 7) for a reference to sleeping in a dark room ; and on fol. 5 b (p. 24) it is mentioned that R. Eleazar, who was very poor, was lying in a dark room. According to Lane, p. 145, Orientals have their supper "shortly after sunset." In J. T. it is mentioned that the inhabitants of villages leave the fields before nightfall for fear of wild beasts.

[THE BARAISA SAYS THAT THE TIME FOR RECITAL OF SHEMA IS] FROM THE TIME THAT A POOR MAN ENTERS [HIS HOME] TO EAT HIS BREAD WITH SALT, [UNTIL THE TIME THAT HE STANDS UP TO TAKE LEAVE FROM HIS MEAL]. If we take this literally, the time to recite Shema is a very small window. Let us assume that the poor man arrives home at six p.m. and his meal lasts till six thirty p.m. He must recite Shema and pray within this period. This is bewildering! When will the poor man himself pray? For you are saying that only the time of his meal between six and six thirty p.m. is the time for recital of Shema, and as soon as the time for recital of Shema at his mealtime arrives it is forbidden to begin a meal until he first prays, as we learn in a Baraisa later (4b): One recites Shema and prays first and then eats his bread and recites a blessing for the meal he has eaten. Whoever transgresses the words of the Sages and eats before praying is liable for the death penalty. If he cannot eat his meager meal first, when will he pray?¹Perhaps he should postpone his meal somewhat? For example, if the time that he comes home to eat is six p.m., he should first pray and recite Shema and then eat. מהרש"א explains that Tosfos does not consider this a possibility. The reason that he comes home to eat so early is because he does not have sufficient artificial light as Rashi explains. If so, his meal cannot be put off, because he will not have sufficient artificial light to eat his meal.
We can answer: The time for prayer is before the time of his meal. But isn’t his mealtime the time for recital of Shema? The time mentioned in the Baraisa - “when the poor man enters to eat his meal” is imprecise, rather, [the Gemara] means slightly before his mealtime. So that while his meal is being prepared, he can recite Shema and pray the eighteen Berachos.²See תוספות הרא"ש who explains that the word נכנס לאכל implies that that the time is not exactly when he begins his meal, rather when he comes home and the meal is prepared. During the preparation, he recites Shema and prays. He arrives home at five forty five, his meal is prepared till six. During that time he recites Shema and prays.