From Sahih Bukhari (Hadith 6554):
Narrated Sahl bin Sa`d:Allah's Messenger (ﷺ) said, "Seventy thousand or seven hundred thousand of my followers will enter Paradise. (Abu Hazim, the sub-narrator, is not sure as to which of the two numbers is correct.) They will be holding on to each other, the first will not entering the last one does, their faces like the moon on a full moon night
Reference: Bukhari 6554