The term al-mufarridūn has been transmitted both with a doubled r and with it lightened, but the reading preferred by the majority is the one with the doubling.

Explanation
These narrations all illustrate the virtue of remembering Allah. Concerning the first ḥadīth, the Messenger of Allah ﷺ said, “The likeness of the one who remembers Allah and the one who does not remember Him is that of the living and the dead.” The reason is that whoever remembers Allah—the Exalted—has his heart enlivened by that remembrance and his breast opened, so he is like a living person. As for the one who neglects to remember Allah, his heart finds no serenity—Allah’s protection is sought—nor does his breast expand to Islam; he is like the dead. A believer should ponder this comparison and realise that whenever he becomes heedless of Allah’s remembrance, his heart hardens and may even die—Allah’s refuge is sought.

The last two ḥadīths likewise underscore the excellence of dhikr. When a person remembers Allah within himself, Allah remembers him within Himself; and when he remembers Allah in an assembly, Allah remembers him in an assembly better than theirs. In other words, if you remember your Lord inwardly—whether by moving your tongue quietly so no one hears, or by calling Him to mind in your heart—Allah, exalted is He, remembers you within Himself. And when you remember Him publicly, in the presence of a group, Allah remembers you in a company superior to that—namely, among the angels—mentioning you before them, exalting your status, and praising you. This demonstrates the merit of dhikr, and that remembering Allah in public is better than remembering Him privately—unless one fears falling into ostentation. Should that fear arise, he ought not to raise his voice, yet he must not allow misgivings to settle in his heart and say, “If I…"