“The church which is His Body” (Eph. 1:22,23) is “built upon the foundation of the apostles and prophets” (Eph. 2:20), referring to grace apostles and prophets (I Cor. 12:28,29). This means that the work of an apostle was foundational in nature. If 2000 years later we are still laying the foundation of the Church, there is something seriously wrong!
Apostles and prophets could speak for God by inspiration of the Holy Spirit, speaking verbally with the same inspired authority that Paul experienced when he wrote his epistles. Paul could not be everywhere at once, and so God needed prophets who could speak with the same authority he enjoyed as he wrote his epistles. Once the Bible was complete, however, “that which is perfect” was come, and the gift of prophecy ceased (I Cor. 13:8-10). Once the gift of prophecy ceased, of course, there were no more apostles and prophets. Within the pages of His Word, God has said all that He needed to say. This is why He closed the Book by pronouncing a curse on any who would add to what was written therein (Rev. 22:18).
With this in mind, it is not just wrong to call a man an apostle today, it is dangerous. Today no man can demonstrate “the signs of an apostle” (II Cor. 12:12), and no man can speak with the authority of the written Word of God. source