Q&A: What is the purpose of ‘ס’ or ‘פ’ following a verse?

These are markers of the traditional Jewish division of the text into parashot (“passages” or “episodes”), which don’t correspond with the chapter divisions devised by Archbishop Langton in the 13th century. The {פ} marker indicates that the parashah (passage) is “open” (ptuḥah), and {ס} means that it is “closed”  (sgurah or stumah).

Examples of a parashah stumah (1) and a parashah ptuḥah (2). In the KJV, they’re both marked simply with a new paragraph sign (3)

The difference between the two types is one of content, and reflected in the typesetting: a parashah ptuḥah marks a significant shift in theme or subject, and so begins at the start of a new line; a parashah stumah is thematically an extension of the previous one, so begins simply nine spaces or more after it—which is usually somewhere along middle of a line, resulting in the line of text being “closed” at either end of the text column (hence the name)—unless there isn’t room for its first word, in which case, it does start a new line (but because it was “obliged” to do so, it still counts as “closed”).

The division into parashot is usually to indicate a contextual change, so there isn’t a consistency in the size or number of verses involved. In the case of the Ten Commandments, for example, each commandment is a parashah in its own right—presumably to underline its importance. Nonetheless, the Babylonian Sages strove to divide the rest of the Torah into 53 or 54 major parashot (episodes), so that one can be read each week at the synagogue.

In the SimHebrew Bible, the two markers are preserved (shown here in bold)—e.g. Numbers 17:21–28:

ca vidbr mwh al-bni iwral, viitnu aliv cl-nwiaihm m’th lnwia akd m’th lnwia akd lbit abotm–wnim ywr m’tot; um’th ahron btoç m’totm.
cb vink mwh at-hm’tot lpni ihvh baohl hydot.
cg vihi mmokrt, viboa mwh al-aohl hydut, vhnh prk m’th-ahron lbit lvi; vioxa prk vixx xix, vigmol wqdim.
cd vioxa mwh at-cl-hm’tot mlpni ihvh al-cl-bni iwral; virau viqku aiw m’thu {p}
ch viamr ihvh al-mwh, hwb at-m’th ahron lpni hydut lmwmrt laot lbni-mri; vtcl tlunotm mylii, vla imutu.
cv viyw mwh:  cawr xivvh ihvh aoto, cn ywh {p}
cz viamru bni iwral al-mwh lamor:  hn gvvynu abdnu, culnu abdnu.
ck col hqrb hqrb al-mwcn ihvh imut; ham tmnu lgvoy {s}

{p}