Ma'arif al-Qur'an
Mufti Muhammad Shafiوَإِذَا قِيلَ لَهُمُ ارْكَعُوا لَا يَرْكَعُونَ (And when it is said to them, "Bow down", they do not bow down...77:48) According to most commentators, the word ruku' is used here in its primitive sense 'to bow down and submit'. The verse signifies that when they were told to submit to the Divine commands, they refused to comply. Some scholars take the word ruku` in its technical sense and interpret the verse to signify 'when they are called to prayer, they refused to pray.' The ruku` is a part of the prayer, but it refers here to the whole prayer. [ Ruh ]