Jami At-Tirmidhi 264 – Prohibition For Qassi, Gold And Quran In Ruku
The prohibited things are prohibited for their cause or Illat. When Illah is there, the prohibition is there, when Illah is removed, the rule stands null. The prohibition of wearing some colored clothes and gold was a show of extravagance or pride, which was disliked, but the prohibition of reciting the Quran in Ruku goes on forever. Ruku is meant for Zkr of God or to praise Him and His glory.