The salve of Allah experiences times of heedlessness, detachment (from Allah), hardening of the heart, disregarding mistakes, and disposes towards sinning during the intervals between the five daily prayers. This deplorable change takes him away from his Lord and prevents him from being near to Him and alienates him from his position as the true slave of Allah. Even worse, he may willingly deliver himself to his enemy (Shaytan) who captures him, puts him in chains and locks him in the prison of his base-desires, causing him to experience nothing but anxiety, grief, sorrow and regret while being unaware of the reason behind his wretched condition.
It is through the Mercy of his Lord, the Most Compassionate, who decreed upon him a comprehensive act of worship made up of diverse phases and formats; each phase and format corresponds to the different actions he committed and conditions he experienced outside the salah. More so, it is designed so that the goodness and benefit he acquires from each phase is in a measure proportionate to his needs, as this act of worship (i.e. salah) is prescribed to demonstrate his servitude to Allah.
Inner Dimensions of the Prayer Ibn Qayyim Al-Jawziyya Pages 26-27