Mat 28:19 is well known to be a forgery.
Some people don't want to know the truth because they are so brainwashed by their tradition.
New Catholic Encyclopedia, 1977 Edition, Vol. 13, p. 1021 -- The first use of the Latin word "trinitas" (trinity) with reference to God, is found in Tertulian's writings (about 213 A.D.) He was the first to use the term "persons" (plural) in a Trinitarian context.
Encyclopedia Americana, 1957 Edition, Vol. 27, p. 69 -- The word "Trinity" is not in Scripture. The term "persons" (plural) is not applied in Scripture to the Trinity.
The New Catholic Encyclopedia states: "The formulation 'one God in three Persons' was not solidly established, certainly not fully assimilated into Christian life and its profession of faith, prior to the end of the 4th century. But it is precisely this formulation that has first claim to the title the Trinitarian dogma. Among the Apostolic Fathers, there had been nothing even remotely approaching such a mentality or perspective." - (1967), Vol. XIV, p. 299.
Nouveau Dictionnaire Universel: "The Platonic trinity, itself merely a rearrangement of older trinities dating back to earlier peoples, appears to be the rational philosophic trinity of attributes that gave birth to the three hypostases or divine persons taught by the Christian churches. . . . This Greek philosopher's [Plato, fourth century B.C.E.] conception of the divine trinity . . . can be found in all the ancient [pagan] religions."
- (Paris, 1865-1870), edited by M. Lachatre, Vol. 2, p. 1467.
World Book Encyclopedia, 1984 Edition, Vol. T, p. 363 -- Belief in Father, Son and Holy Ghost was first defined by the earliest general council of churches. This was the First Council of Nicaea in 325 A.D.
New International Encyclopedia, Vol. 22 p. 476 -- The Catholic faith is this; We worship one God in Trinity, but there is one Person of the Father, another of the Son and another of the Holy Ghost. The Glory equal -- the Majesty co-eternal. The doctrine is not found in its fully developed form in the Scriptures. Modern theology does not seek to find it in the Old Testament. At the time of the Reformation the Protestant Church took over the doctrine of the Trinity without serious examination.
Life Magazine, October 30, 1950, Vol. 29, No. 18, p. 51 -- The Catholics made this statement concerning their doctrine of the Trinity, to defend the dogma of the assumption of Mary, in an article written by Graham Greene: "Our opponents sometimes claim that no belief should be held dogmatically which is not explicitly stated in Scripture ... But the PROTESTANT CHURCHES have themselves accepted such dogmas as THE TRINITY, for which there is NO SUCH PRECISE AUTHORITY In the Gospels."