Sunan at-Tirmithiy كتاب الصلاة باب ما جاء من أحق بالإمامة
Ma'dān Ibn-Talḥah al-Ya'marī said, "I once met Thawbān, the servant of the Messenger of God, peace and blessings be upon him, and said to him, 'Guide me to a deed for which God would reward me, and that would enable me to enter Paradise.' He paused for a moment then turned to me and said 'Keep to prostration[1], for I have heard the Messenger of God, peace and blessings of God be upon him, say, 'No bondsman prostrates to God a single prostration, except that with it, God raises him a rank [in Paradise] and relieves him of [the burden of] a sin.'" Footnotes: [1] i.e. prostrate to God often and prolong your prostrations during prayer, for we are closest to God while in prostration. Click on ḥadīth to read more