‘And recite the Qur’an (aloud) in a (slow and melodious) style
(tarteela)’ (Surah Muzzammil, aayah 4)
Ali ibn Abi Talib (radiallahu ‘anhu) said in the explanation of
this aayah: “at-Tarteel is Tajweed of the letters and knowing where to
stop (correctly)”.[An-Nashr of Ibn Al-Jazaree 209:1]