Using Weak Hadiths in Encouragement and Warning

Question:
This questioner says: Honorable Shaykh, I am one of those who deliver some words in the mosques, and I cite some weak hadiths during my talks on the virtues of deeds.

Answer:
If you are qualified—for example, if you have acquired a great deal of knowledge, either by studying under the shaykhs and they testified to your acquisition, or they granted you a license of acquisition, or through formal study in the colleges of Shari'ah and principles of religion and you graduated from them—then you are qualified. You must strive to cite valid evidence; you must strive to cite valid evidence, especially in matters of what is lawful and what is forbidden. It is not permissible for you to declare something lawful or forbidden except with valid evidence from the Book and the Sunnah. As for encouraging deeds, urging obedience, or forbidding sins and warning against them, a hadith, even if it is weak, is used in this encouragement and warning and in urging the virtues of deeds. However, no legal ruling of lawfulness, prohibition, obligation, or recommended practice is established upon it. Yes.