The Ruling on Acting Upon Weak Hadiths in the Virtues of Deeds

Question:
It has become common among many people to act upon weak hadiths on the pretext of the virtues of deeds, without observing the conditions set by the scholars for this, until it became their habit; this has deprived them of sensitivity and concern for the correct, established evidence from Allah and His Messenger (peace and blessings be upon him). This has led them into religious innovation, and consequently into shirk (associating partners with Allah) through their exaggeration regarding the Messenger of Allah (peace and blessings be upon him), which led them to call upon him for aid and to supplicate to him, relying on no evidence, or on one whose foot slipped and whose knowledge of what the righteous predecessors were upon was little. We ask your Eminence for guidance, and may Allah reward you with good.

Answer:
Weak hadiths are not relied upon to establish anything of the Shari'ah. The same applies to stories, dreams, sayings, and reports from some of the predecessors; none of these are relied upon to establish a legal ruling. Rulings are established by the verses of the Qur'an, or by the established hadiths of the Messenger of Allah (may Allah's prayers and peace be upon him), or by what comes from the Rightly Guided Caliphs. As for weak hadiths, no, no ruling is established by them, neither an obligatory act, nor a recommended practice, nor a prohibition, nor a disliked act. This is only established in hadiths.
However, the scholars mentioned that weak hadiths are mentioned in the context of encouraging things that are known from the religion, not in the context of newly invented matters. For this reason, they are lenient with weak hadiths, not fabricated ones, specifically with weak hadiths whose chains of narration are not sound but which are not false. As for the false, the fabricated, no, it is never mentioned except to clarify that it is a lie, and it is never cited as evidence.
But the hadiths that contain weakness, whether due to a narrator with poor memory, or a narrator who has some degree of open sinfulness, or something similar to what is said: that his hadith is weak, these are mentioned by the scholars in the context of encouraging known righteous deeds. For example: weak hadiths in the context of charity. Charity is known; there are verses regarding the command of charity, and there are authentic hadiths. So if some weak hadiths come regarding the virtue of charity, they are mentioned. Or regarding the virtue of prayer and voluntary prayer, or the virtue of tasbih (glorification), or tahlil (saying La ilaha illa Allah), or the dhikr (remembrance of Allah). All these are known matters. So they may be lenient with weak hadiths because their basis is known, and because the acts of worship mentioned in the weak hadiths are a known matter from the Book and the Sunnah. This is one aspect.
As for the weak hadith that establishes a new act of worship, no. Weak hadiths do not establish an act of worship, nor a prohibition, nor a disliked act, nor an obligatory act. So those who establish new acts of worship by them are mistaken.