Talmud for Pesachim 99:26

HALAKHAH: Rebbi Simon in the name of Rebbi Joshua ben Levi: It is written, on that day will all shadow of horses be holy¹⁵³Zach. 14:20. Cf. Babli 50a. etc.; to the place where the horse runs without having a shadow¹⁵⁴The future size of the suburbs of Jerusalem will be as far as a horse can run outside the walls of Jerusalem during noontime at the summer solstice when it casts no shadow (Rashi in the Babli, explanation by R. Makhir.).