Genesis 3:15 is commonly called the "Protoevangelium", meaning "The first Gospel". This is because it contains the first reference to the Messiah in the Bible - the promised seed of the woman who will "bruise the head of the serpent", who is Satan (Revelation 12:9, 20:2):
Genesis 3:15
15 And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
Notice above, that the seed of the woman, Jesus Christ, will be the one to bruise the head of the serpent, while the serpent will bruise His heel - a reference to the temporary anguish of the cross. Jesus crushed the head of the serpent when He conquered death (Colossians 2:14-15, Hebrews 2:14-15: 1 John 3:8).
Therefore, Genesis 3:15 is extremely valuable to us in establishing that God has always preached the Messiah that would redeem mankind to every generation. This first promise made to Adam and Eve is the basis from which all the prophets preached the same message of the Messiah which was to come (Acts 10:43, 26:22-23). And, when witnessing to Muslims and Jews, especially, the reference to the "bruising of His heel" is invaluable, because it points to something that they both reject - the crucifixion of the Messiah.
The Latin Vulgate has been the official translation of the Catholic Church for many hundreds of years. It was so enshrined, that at the Council of Trent (1545-1563 AD), it was forbidden to be rejected "under any pretext whatsoever":
The Council of Trent (1546 AD)
Moreover, the same sacred and holy synod, considering that no little utility may accrue to the Church of God, if, out of all the Latin editions, now in circulation of the sacred books, it be known which is to be held as authentic, ordains and declares, that the said old and vulgate edition, which, by the long usage of so many ages, has been approved in the Church, be, in public lectures, disputations, preachings, and expositions, held as authentic; and that no one is to dare, or presume to reject it under any pretext whatsoever.
However, the Protoevangelium, in the Latin Vulgate, contains an indisputable error. This error can be seen in the Duoay-Rheims version of the Bible, which is a translation of the Latin Vulgate into English:
Genesis 3:15 (Duoay-Rheims)
15 I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel.
Notice that the Vulgate mistook the gender of the second clause of this sentence. The pronouns refer to the antecedent "seed", and consequently, they are rendered "he" and "his" in virtually every other translation of the Bible, but could also be rendered "they" and "their", if one wanted to argue that multiple descendants were in mind. In no case could it only be rendered "she" and "her".
Consequently, if all that a person had was the Latin Vulgate, they would be utterly unequipped to find the Lord Jesus in the Protoevangelium that God gave us. Instead, their eyes would be turned toward Mary as having "crushed the head of the serpent", which is exactly how this passage in the Vulgate was historically applied by Roman Catholics. The Vulgate, instead of pointing toward the Lord Jesus, accelerated Mariolatry.
This is why, in Catholic statuary, it's common to see Mary depicted standing on a serpent - not so with Christ. The glory of Christ's conquering of the Devil has been taken from Him, and given to Mary, on the basis of this mistranslation.
Further, when Pope Pius IX (1792-1878 AD) promulgated Ineffabilis Deus, which made Mary's Immaculate Conception a dogma to be believed on pain of Anathema, he repeatedly referenced the Vulgate's erroneous rendering of the Protoevangelium, and used it to argue that Mary crushed the head of the serpent:
Pope Pius IX - Ineffabilis Deus (1854 AD)
These ecclesiastical writers in quoting the words by which at the beginning of the world God announced his merciful remedies prepared for the regeneration of mankind — words by which he crushed the audacity of the deceitful serpent and wondrously raised up the hope of our race, saying, "I will put enmities between you and the woman, between your seed and her seed" — taught that by this divine prophecy the merciful Redeemer of mankind, Jesus Christ, the only begotten Son of God, was clearly foretold: That his most Blessed Mother, the Virgin Mary, was prophetically indicated; and, at the same time, the very enmity of both against the evil one was significantly expressed. Hence, just as Christ, the Mediator between God and man, assumed human nature, blotted the handwriting of the decree that stood against us, and fastened it triumphantly to the cross, so the most holy Virgin, united with him by a most intimate and indissoluble bond, was, with him and through him, eternally at enmity with the evil serpent, and most completely triumphed over him, and thus crushed his head with her immaculate foot.
Pope Pius IX - Ineffabilis Deus (1854 AD)
They also declared that the most glorious Virgin was Reparatrix of the first parents, the giver of life to posterity; that she was chosen before the ages, prepared for himself by the Most High, foretold by God when he said to the serpent, "I will put enmities between you and the woman." - Unmistakable evidence that she crushed the poisonous head of the serpent.
Pope Pius IX - Ineffabilis Deus (1854 AD)
All our hope do we repose in the most Blessed Virgin — in the all fair and immaculate one who has crushed the poisonous head of the most cruel serpent and brought salvation to the world
The above is an egregious misuse of Scripture, justified by appealing to a mistranslation, and it constitutes a substantial part of his argument in favor of Mary's Immaculate Conception.
Finally, note that in the 1979 revision of the Vulgate - the first such revision in over 380 years - the reading of the Protoevangelium was changed to "he" and "his", brining it in line with virtually every other Bible. This is a tacit admission that it was in error, for all of that time, even though the results of that error - further Marian exaltation - remain firmly in place.
Any person using the Latin Vulgate prior to 1979 AD would have been disabled from preaching Jesus from the Protoevangelium, because of an error that it contained. Yet, the Council of Trent ruled that no one may "presume to reject it under any pretext whatsoever".
This is an instance where dogmatism absolutely affects doctrine, one's ability to learn, and one's ability to get the truth from God's Word, because of the enshrining of the work of very fallible sinners. If the Catholic Church was indisputably wrong to rule that none could reject their errant, fallible Vulgate "under any pretext whatsoever", why should we take their other claims of authority seriously?
While the Council of Trent (1545-1563 AD) established the Vulgate as authoritative, it did not specify which edition of the Vulgate was to be regarded as the standard version.
As a result, Pope Sixtus V (1520-1590 AD) took it upon himself to issue his own edition of Vulgate in 1590 AD, which he defined to be the authoritative version mentioned in Trent, despite, obviously, the fact that it didn't even exist until over 25 years after the Council of Trent concluded. This Sixtine Vulgate, as it is called, was published with the Papal Bull Aeternus Ille affixed to the introduction, which says:
Pope Sixtus V - Aeternus Ille (1590 AD)
In this very amendment of the Vulgate edition, we have used especially important matters, and from our sure knowledge, and with the fullness of the Apostolic power, we have established and declare that the Vulgate is the Latin edition of the sacred pages of both the Old and New Testaments, which was accepted as authentic by the Council of Trent is, without any doubt or controversy, to be considered this very one, which now, as best possible, corrected and printed in the Vatican Typography, we publish to be read in the whole Christian Republic and in all the Churches of the Christian world, deciding, first of all, to the universal holy Church, and with the consent of the holy Fathers, then by the decree of the General Council of Trent, and now finally also the Apostolic authority handed down to us by the Lord, confirmed as true, legitimate, authentic, and indubitable, to be received in all public and private discussions, readings, preachings, and explanations, and to be maintained.
In the above Bull, Pope Sixtus is declaring his revision to be the "indubitable" standard. He died a few months after the first printing, which has been scanned and uploaded to the Internet Archive, where anyone can see the Bull cited above to be authorized by Pope Sixtus, and published in the Bible itself.
The issue? The issue is that everyone totally rejected his version of the Vulgate. The Church suspended sale of it 9 days after he died, and his successor, Pope Clement VIII (1536-1605 AD), ordered Pope Sixtus V's edition of the Vulgate to be recalled in 1592 AD - two years after it was published. Pope Clement VIII then revised it, and his version, called the Sixto-Clementine Vulgate, is what would be used until 1979 AD.
So, the Council of Trent declared that the Vulgate was to be held as authentic, but failed to define the authoritative edition, leading to a later Pope publishing his own edition as the authoritative version, even though that was swiftly rejected and discarded after he died. Then, another Pope would further revise it, and that further revision would become the accepted edition for the next 380 years.
Therefore, no one can reject the text "under any pretext whatsoever", even though no one was sure what that text was even supposed to be, and the first attempt to canonize a standard edition was universally regarded to be a failure, even though the "Vicar of Christ" who was making the attempt declared it to be the authoritative standard at the time.