Consider Ayat 14, Surah Ta-Ha..

As-Salaam alaikum,
  In ayat 14 of Surah Ta-Ha of the Holy Qur'an (20:14), Allahu, Tabaraka Wa Ta'ala, says:--

        "VERILY, I AM ALLAH:
        THERE IS NO DEITY [god] BUT I:
        SO SERVE ME (only),
        AND ESTABLISH REGULAR (Sallaat) PRAYER
        FOR CELEBRATING MY PRAISE (Zikr).''

 Establishing Sallaat means having spiritual connection with Allah Ta'ala and observing Him in the heart, as the Prophet, Sallallahu alaihi Wasallam, said:--

        "There is no Sallaat without the presence of heart (before Allah)".

In Sallaat with presence of heart, our organs are busy in bowing and prostrating, the tongue will be reciting the Qur'an but the heart is engrossed in the remembrance and vision of Allah.