Three - Vine's Expository Dictionary of New Testament Words
Three[ 1,,G5143, treis ]
is regarded by many as a number sometimes symbolically indicating fullness of testimony or manifestation, as in the three persons in the Godhead, cp. 1 Timothy 5:19; Hebrews 10:28; the mention in 1 John 5:7 is in a verse which forms no part of the original; no Greek ms. earlier than the 14th century contained it; no version earlier than the 5th cent. in any other language contains it, nor is it quoted by any of the Greek or Latin Fathers" in their writings on the Trinty. That there are those who bear witness in Heaven is not borne out by any other Scripture. It must be regarded as the interpolation of a copyist.
In Mark 9:31; Mark 10:34 the best texts have meta treis hemeras, "after three days," which idiomatically expresses the same thing as te trite hemera, "on the third day," which some texts have here, as, e.g., the phrase "the third day" in Matthew 17:23; Matthew 20:19; Luke 9:22; Luke 18:33, where the repetition of the article lends stress to the number, lit., "the day the third;" Luke 24:7, Luke 24:46; Acts 10:40. For THREE TIMES See THRICE.