On erev shabbos when davening before tzais, do men have to wait until tzais to say shema over again and only then start their seudah? Or since they said kriyas shema already (in shul-early) they can start their seudah when they get home and say shema later on? Thank you
If there is less than half an hour to go before tzeis hakochavim, it is not permitted to begin the meal, and one must wait until tzeis and say kriyas shema before eating. If there is more than half an hour to go, it is permitted to begin the meal, and one can recite kriyas shema again after finishing the meal (there is no need to stop in the middle, because the meal was started with halachic permit).
Although the Maamar Mordechai (267:2) brings an opinion who writes that because one has already said Kriyas Shema early, it is permitted to begin to eat even with half an hour of tzeis, he defers this ruling based on the Magen Avraham (235:4) and others, and the consensus of authorities is that once within the half an hour range of tzeis hakochavim, one must wait until tzeis to recite kriyas shema.