Rashi: He will play.

Rashi: It is the cavity in the earth in which a snake nests. Pasen is an old snake; it becomes deaf, and it does not hear snake-charming whispers - "Asher Lo Yishma l'Kol Melachashim" (Tehilim 58:6).

Rashi citing Targum Yonasan: The vision of the eyes of a Churman ¹ snake. Radak - i.e. the snake's eye illuminates, and a child who sees it from outside [the hole] thinks that it is a gem or glass, he sends his hand to take it, and touches the snake; it will not harm him.

Rashi citing Menachem: It is an expression of a hole, and cavities in earth. The same applies to "Ohr Kasdim" (Bereishis 11:28) and "ba'Urim Kavdu Hashem" (below, 24:15). Radak - also "ha'Minharos Asher be'Harim" (Shoftim 6:2) are caves. They are called so, for they have a hole via which Ohr (light) enters.

Malbim: It is its venom. It will not harm one who touches it, for it will not have venom, just a shiny substance.

Rashi: It is an infant that was weaned from nursing. Radak - toddlers often stick their hands in the ground of the house or holes in the wall.

Rashi citing Targum Yonasan: He will stretch his hand. This is like "Hed Harim" (Yechezkel 7:7), "Heidad" (below, 16:9). There, it is raising the voice; also here, it is raising. The Hei at the end of Hadah is part of the root; sometimes it is omitted, like Asah, Banah, Kanah.

Radak: Hadah is like Yadah; he sent his hand. Hatred of the snake, which was decreed in the days of Bereishis, will depart in all of Eretz Yisrael and for Am Yisrael wherever they go. Snakes and Chayos will not harm them.