Chazal tell us (and this is the halachah in the Shulchan Aruch) that a person should complete the parsha of the week (reading it twice) and the Targum (once) every week…and that those who do this will have length of days and years. By “always” they mean that even a person who is pressured by a heavy schedule of learning Torah and has no time—even he should be careful to read the parsha with the Targum as required. The repetitious “length of days and years” comes to suggest that his life will be good as well as long. Rav Bibi bar Abaye was descended from the children of Eli Hacohen, whose descendents were destined to live short lives. The Gemara tells us that since on Rosh Hashanah the books of life and death are open, and completing the parshas is a segula for length of days, he made a point of completing the reading of all the parshas of the year by erev Rosh Hashannah so that he might be inscribed in the book of life immediately.