Related for Megillah 43:20

We do not read fewer than three verses from the Torah at one time. If there was a section with four [verses] or of five [verses] (i.e., which cannot be divided into two or more sections of three), behold, one person reads the whole thing. [If] there was a section of five and he read three and left out the other two, the one who stands up to read after him reads those two and another three from a different section. If there was a section of four or five [verses], behold, he reads everything. We may not read an additional [portion from the] Prophets (i.e., the haftarah) of less than three verses at one time. If there was a section of four or five verses, behold, he reads everything. One who cuts short [the reading], behold he is praised. If it was a short section, such as (Is. 42:3), "For thus says the Lord, you were sold for nothing, and you shall be redeemed without money," it is read by itself.