Trumpet Call exists to warn Christians of the coming judgment and the wrath of God if they continue in their sins.
Ezek 33:2b-6 When I bring the sword upon a land, and the people of the land take a man from their territory and make him their watchman, when he sees the sword coming upon the land, if he blows the trumpet and warns the people, then whoever hears the sound of the trumpet and does not take warning, if the sword comes and takes him away, his blood shall be on his own head. He heard the sound of the trumpet, but did not take warning; his blood shall be upon himself. But he who takes warning will save his life. But if the watchman sees the sword coming and does not blow the trumpet, and the people are not warned, and the sword comes and takes any person from among them, he is taken away in his iniquity; but his blood I will require at the watchman’s hand.
Being a Protestant Christian, it is easy for us to simply say, we believe in the Bible. But, there are lots of different interpretations of the Bible and several deceptions without sound doctrine which created thousands of denominations. Hence, we had put forward a Circle of Discernment to discern every interpretation from the Bible to avoid deceptions.
Circle of Discernment is another way of saying, all interpretations must match God’s spoken words, Christ’s teachings, Scripture (Law, Psalms and Prophets) and the teachings of apostles and disciples in the authoritative order. If you cannot find the conclusion of your interpretation taught by Christ, or found in Scripture, or spoken by God in the authoritative order, then your interpretation is wrong. Similarly, if you interpret Scripture that does not agree with Christ, then your interpretation is wrong.
Christ did not gave anyone authority to change His canon of Scripture (Luke 24:44-45). He included only 28 books from the Christian Bible: Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Joshua, Judges, I & II Samuel, I & II Kings, Isaiah, Jeremiah, Ezekiel, Daniel, Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum, Habakkuk, Zephaniah, Haggai, Zechariah, Malachi and Psalms. Just like there are weightier matters of the law (Matt 23:23), Gospels and Revelation are the weightier books in the New Testament. We need to listen and obey Christ’s teachings for which Father will require of all who reject His Words spoken through His Son (Deut 18:19). It is blasphemy to exalt and glorify a man’s letter and make it equal with Christ’s words.