Shulchan Arukh, Orach Chayim 138

To Not Leave Over Less Than 3 Verses In a Parsha. Containing 1 Se'if:
The one who reads from the Torah may not leave over any less than 3 verses in a paragraph because [we are concerned for] those who leave the synagogue then, that they will say that the oleh (i.e. reader) after him will only read the two remaining verses [of the paragraph]. And similarly, one may not begin less than 3 verses into it (i.e. a paragraph) because of those who enter the synagogue then, that they will say that the first [reader] only read 2 verses. Rem"a: And there is no difference between an open paragraph and a closed paragraph. And a paragraph that only has two verses: it is permitted to leave over [these two verses] at the beginning [of a paragraph] and to stop there (T'rumat HaDeshen, siman 22). And one should aim to always begin to read on a good matter and to end on a good matter (Or Zarua and Meimoni, Chapter 13 of Hilkhot T'fillah). And see below, Chapter 428.