Is it permissible to act upon a weak hadith, and what is the authenticity of the hadith: "Hold fast to night prayer, for it was the practice of the righteous before you, and indeed, night prayer is a means of drawing closer to Allah, a deterrent from sin, an expiation for misdeeds, and a repeller of illness from the body"?

It is permissible to act upon a weak Hadith (definition) under certain conditions. The Hadith mentioned: "You should observe the night prayer, for it was the practice of the righteous before you, a means of drawing closer to Allah, a deterrent from sin, and an expiation for evil deeds." Al-Albani graded this narration as authentic, while he deemed the wording "and a驱逐 of disease from the body" as weak. It was also narrated with another wording: "You should observe the night prayer, for it was the practice of the righteous before you, it is a means of drawing closer to your Lord, an expiation for evil deeds, and a deterrent from sin," and Al-Albani graded this as good (hasan (definition)).