Tawbah naṣūḥ. Sincere tawbah. The word means pure, unmixed, undiluted. Most of our tawbah is mixed: words plus intention to return. Pure tawbah is the door.

There is a moving narration about ʿUmar ibn al-Khaṭṭāb. He was sitting in the masjid, weeping. A companion asked: O Amīr al-Muʾminīn, why do you weep? He said: I just made an oath against making the same sin I just repented from, and I am afraid I will break the oath. The companion said: there is mercy. ʿUmar said: but the mercy is for sincere tawbah; my fear is that I am not sincere enough. The Salaf's fear was not of Allah's reluctance to forgive; it was of their own incomplete sincerity. We have the opposite fear. We assume our tawbah is sincere because we said the words. The honest believer audits the sincerity. Tonight, before sleep, pick one sin you have been carrying. Now apply the four pillars: leave it (have I actually stopped, or am I only pausing?); regret it (do I actually feel the wrongness, or am I performing the regret?); intend never to return (do I have a plan to prevent recurrence, or am I leaving the door open?); return any rights (if I wronged someone, have I tried to make it right?). Walk through the four. Make the tawbah. Then make a tawbah for the incompleteness of the tawbah itself. Allah's mercy covers what we cannot fully do. Yā Allāh, accept our incomplete tawbah by Your perfect mercy. Make us of those whose tawbah was naṣūḥ, and admit us by Your promise into the gardens You named. Āmīn.