in a very short span: quickly, without delay, or soon. The same word covers how fast something happens and how little time passes before it does.
This little adverb is built from a family of Greek words for speed. Across ordinary Greek it pulls in two directions that English keeps in separate words but Greek does not: the manner of an action (it is done fast, at once, without delay) and the nearness of an event in time (it is about to happen, before long). The two shade into each other, because something done with no delay also tends to happen soon.
In plain narrative the manner reading usually wins: people move, rise, or run with this word, and the picture is one of haste rather than a calendar. But when it modifies a verb about something still to come, especially a promise or a prophecy, the same word naturally means "soon".
Most of the weight this word carries comes from the book of Revelation, where the risen Jesus says it again and again: I am coming quickly. Readers and scholars have long argued over whether that means "soon" (within the first readers lifetime) or "suddenly" (a rapid arrival once it begins). The careful lexicons that separate the two senses place the Revelation promises on the time side: soon. But the manner of speed never fully drops away, which is why English translators stay split between quickly and soon. The word does not settle the question of how long the wait will be; it presses the reader toward urgent expectation either way.