How can one who performs the night vigil prayer be considered a hypocrite or a dissimulator, whose deeds are thereby invalidated, knowing that the night vigil prayer is one of the secret acts of worship, which is considered contrary to hypocrisy and dissimulation?

The prophetic hadith sheds light on people who will come on the Day of Resurrection with tremendous good deeds, but Allah will render them as scattered dust because when they were alone with Allah's prohibitions, they violated them. Therefore, night vigil (Qiyam al-Layl) is not immunity from sin. Humans are complex; they do good and fall into evil. Acts of worship may lack devotion or be tainted by hypocrisy. Night vigil does not prevent one from falling into sins, and this is not inconsistent with deficient deeds. Greater than night vigil is the obligatory prayer, yet we see those who pray it while committing sins. The Prophet, peace and blessings be upon him, described the Khawarij as performing night vigil, yet they deviated from the religion. The heart is what matters most; one should not be deceived by their outwardly righteousness.