Is the Hadith, "Whoever invokes blessings upon me a hundred times, Allah will invoke blessings upon him a thousandfold, and whoever increases in longing and yearning, I will be an intercessor and a witness for him on the Day of Resurrection," sound in terms of its chain of narration, and is it permissible to act upon it?

Al-Hafiz Al-Sakhawi said, after quoting the hadith from the narration of Abu Hurayrah: "Abu Musa Al-Madini transmitted it with a chain of transmission that Sheikh Mughlatay said: 'There is no harm in it.'" We have not found any scholar who transmitted Abu Musa's chain of transmission for us to be able to judge its authenticity. It is permissible to act upon this hadith, even if its chain of transmission is weak, provided that one does not assert its authenticity or its definitive attribution to the Prophet, peace and blessings be upon him. This is because it falls under the category of virtuous deeds and is subsumed under a general principle, and its weakness is not severe, as it has been judged to have "no harm in it."