故名哪吒 The Two Characters On His Palms
父見子以劍架刀，就當喝退，怎麼返大驚失色？原來天王生此子時，他左手掌上有個「哪」字，右手掌上有個「吒」字，故名哪吒。父见子以剑架刀，就当喝退，怎么返大惊失色？原来天王生此子时，他左手掌上有个「哪」字，右手掌上有个「咤」字，故名哪咤。
逐句解 Line by line
When a father sees a son block his blade with a sword, he should shout him down. Why should he go white with shock instead?
The narrator asks the reader's own question and answers it at length — the storyteller's habit that this novel never lost. 子 takes zǐ, the formal reading, because this is the abstract pairing of father and son rather than somebody's child. 喝 is hè, to shout at somebody, in 喝退 — to shout a person back. It is not the hē of drinking.
It turns out that when the Heavenly King fathered this son, there was the character NA on his left palm and the character ZHA on his right, and so he was named Nezha.
A name written on a newborn's hands. 哪吒 is in fact a Chinese shortening of a Sanskrit name — Nalakuvara, a yaksha prince — and the two characters were chosen for their sound, with no meaning of their own. So the story has it backwards, charmingly: the marks came first and the name was read off them. The novel is explaining a foreign name the way folk etymology always does, by inventing a Chinese reason for it.
The digression opens with a birth marvel, which is the correct opening for a saint's life and exactly what this is. Nezha's story circulated on its own long before it was fitted into this novel.
The palm-characters are the sort of detail that sounds ancient and is in fact a puzzle being solved backwards. Somebody had to account for two Chinese characters that meant nothing, and a pair of marks on a baby's hands did the job.