What is the meaning of "promising evil, such as disbelief, فسق (disobedience), and injustice" and "promising good, such as prayer and fasting"? Are these two types of promises specific to Muslims, or to both Muslims and disbelievers? Did Al-Albani retract his weakening of the hadith or his authentication of it, and what was his reasoning?

Al-Albani first weakened this hadith, then authenticated it. The defect in the hadith lies in the confusion of 'Ata' ibn as-Sa'ib, and Abu al-Ahwas's hearing from him after his confusion. "Threatening with evil" means commanding it, such as disbelief, فسوق (transgression), and sins. As for the angel's promise of good, it includes prayer, fasting, charity, and believing in Allah's books and messengers. The phrase "Son of Adam" in the hadith is general, encompassing both believers and disbelievers. The noble verse, "Satan threatens you with poverty and enjoins upon you immorality, while Allah promises you forgiveness from Him and bounty" (2:268), is addressed to all people, not just believers.