you have verified the matter and it has become clear to you. Then, if you discern some benefit in speaking, speak; but if you see no benefit, keep silent. “Whoever believes in Allah and the Last Day, let him speak good or remain silent.”
As for the third hadith: it tells us that a person may utter a single word that earns Allah’s good pleasure—a word that pleases Him, such as reciting a verse of the Quran, glorifying Him, proclaiming His greatness, affirming His oneness, enjoining the right, forbidding the wrong, teaching knowledge, reconciling between people, and the like. He speaks a word that pleases Allah and gives it no particular thought—that is, he never imagines it will raise him as high as it does, even though he understands its meaning and significance—yet Allah raises him by that very word to lofty ranks in Paradise.
Conversely, another person may say a word that incurs Allah’s wrath and likewise pays it no mind, and he plunges into the Fire because of it; he spoke without realizing how far it would take him. This occurs often. Many people—may Allah protect us—when asked about a certain sinner will say, “Leave him; by Allah, he does not know the path. By Allah, Allah will never forgive him.” Such words are perilous indeed.
There was once a devout worshiper who would pass by a sinner, and the worshiper would declare, “By Allah, Allah will never forgive so-and-so.” Observe—Allah preserve us—how he restricted what Allah had made vast and presumed upon his Lord: “By Allah, Allah will not forgive so-and-so.” This worshiper was impressed with his own deeds, flaunting them before his Lord as though he had a claim over Allah. So he said, “By Allah, Allah will never forgive so-and-so.” Allah, Exalted is He, responded: “Who is this who swears an oath by Me that I will not forgive so-and-so? I have forgiven him and nullified your deeds.” To whom belong dominion and authority? To Allah alone. They are not yours that you should dare say, “By Allah, Allah will never forgive so-and-so.”
Sovereignty and might belong to Allah; whoever contests Him for them, Allah will humiliate. He said: “Who is it that dares to swear by Me that I will not…"