The following is an excerpt from Dr. Thomas Holland's Crowned With Glory, ©2000, used with permission.
For an angel went down at a certain season into the pool, and troubled the water: whosoever then first after the troubling of the water stepped in was made whole of whatsoever disease he had.
This verse is usually consigned to footnotes in most modern English versions, and is generally considered an addition by some scribe in order to convey a traditional story regarding the healing pool at Bethesda. Yet, to consider this text as a figment of tradition is conjecture. The passage should be considered genuine since it appears in the Greek Textus Receptus, the majority of all existing Greek manuscripts, the Authorized Version, and the New King James Version.
If we are to accept a reading based on its wide geographical distribution, we should accept this reading because it has old textual support with the greatest amount of geographical distribution. It is found in codices A, E, F, G, H, I, K, L, D, Q, P and the third corrector of C. The Greek minuscules overwhelming support the verse and is contained in 28, 565, 700, 892, 1009, 1010, 1071, 1195, 1216, 1230, 1241, 1242, 1253, 1344, 1365, 1546, 1646, and 2148. It is also included in the majority of Old Latin manuscripts and early translations.
The verse is found in the Old Coptic Version as edited from the Coptic manuscript Huntington 17 and is translated into English as follows:
There was an angel (who) came down every hour in the pool, and moved the water. And any one (who) shall come down first after the moving of the water shall be healed of every sickness which (may) be his. 
The same is true of the Old Syriac. James Murdock's translation of this passage from the Peshitta reads:
For an angel, from time to time, descended into the baptistery, and moved the waters; and he who first went in, after the moving of the waters, was cured of whatever disease he had. 
The passage also has patristic citations. It is found in the Diatessaron of the second century. Tertullian (200 AD) notes that an "angel, by his intervention, was wont to stir the pool at Bethsaida."  The passage is also cited by Ambrose (397 AD), Didymus (398 AD), Chrysostom (407 AD) and Cyril (444 AD), demonstrating that both Greek and Latin fathers accepted the reading as genuine.
 The Coptic Version Of The New Testament: In The Northern Dialect, vol. II (Oxford: Clarendon Press, 1898), 377-379.
 Murdock, 172.
 The Writings Of Tertullian 3:2:5.