EXTRA · Parashas Vayeishev · Passuk 38:5 · not a Torah Temimah citation on this passuk
Once again she bore a son, and named him Shelah; he was at Chezib when she bore him.
Classical source (EXTRA side-ring): Yalkut Shimoni 145.
English: “And she called his name Shelah” — for he was set aside from the world, or because Yehudah sought that he be left in peace (yishaleh).
Derash on the verse (Yalkut) — not a formal named middah of the 13. Naming is read as parental intent.
Shelah’s name encodes Yehudah’s wish to keep this son safe after the deaths of Er and Onan.