Moroni not only saw our day, he provided us with the needed ammunition for our doctrinal battles. He knew that there would be those who would deny any new revelation, prophecy, or gifts of the Spirit. He provided us with the arguments we need to combat this falsehood. What is that argument? It is that God is the same yesterday, today, and forever (v. 9). The implication is that if God loved his children enough to give them revelation in Moses' day, he should do the same in our day. If the ancients had faith enough to perform miracles, then sufficient faith should produce the same results today, wherefore, if these things have ceased wo be unto the children of men, for it is because we of unbelief and all is vain (Moroni 7:37).
We should appreciate the efforts of the Book of Mormon prophets. Beginning with Nephi, they have been concerned with how we should face the doctrinal errors of the last days. Accordingly, Nephi spoke of those who would cry, 'A Bible! A Bible! We have got a Bible, and there cannot be any more Bible' (2 Nephi 29:3). Jacob and Alma taught us how to respond to doctrines of an anti-Christ (Jacob 7, Alma 30). Christ taught us what the name of the church should be (3 Nephi 27:3-8). Moroni taught us how to respond to those who would deny any new revelations, prophecy, or miracles (v. 7-10). Mormon taught us about the practice of infant baptism (Moroni 8:5). Thus, the Book of Mormon prophets were concerned enough with the false doctrines of the last days that they taught us how we should respond to them.