Psa 81:3 Blow up the trumpet in the new moon, in the time appointed, on our solemn feast day.
Hos 8:1 Set the trumpet to thy mouth. He shall come as an eagle against the house of the LORD, because they have transgressed my covenant, and trespassed against my law.
Joe 2:1 Blow ye the trumpet in Zion, and sound an alarm in my holy mountain: let all the inhabitants of the land tremble: for the day of the LORD cometh, for it is nigh at hand;
Joe 2:15 Blow the trumpet in Zion, sanctify a fast, call a solemn assembly:
Mat 24:31 And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.
1Co 15:52 In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
Rev 8:2 And I saw the seven angels which stood before God; and to them were given seven trumpets.
These verses above are a small example of the importance of trumpets and why we should at least know and understand this particular feast appointed by God. This is a holy convocation without a name, basically that means a holy practice for what is to come and that in particular there is no set name for these days of celebration and solemn reflection. It has become a two day feast in that it is impossible to know the day or the hour in which the new moon will show itself. It is the head of the year, therefore regarded as Rosh Hashanah and the day of the blowing of trumpets or Yom Teruah. It is also a day that traditionally is though of as the birthday of creation. What I find especially significant is the fact that they have to watch for the new moon to appear, which then signifies the beginning of the feast, they do not know the day or the hour of it's appearance, just as it states in Mat 25:13, 'Watch therefore, for ye know neither the day nor the hour wherein the Son of man cometh. ' It is also an interesting thought that in the Gospel of John we find his mentioning of the feast of Passover and the feast of Dedication (Hanukah), but in John 5:1 it simply says, 'After this there was a feast of the Jews; and Jesus went up to Jerusalem.' Could this be the feast without a name? I think so. They were required to appear in Jerusalem three times a year and this feast is one of those times. Interesting...
Of course, we are not required to celebrate in order to be one of God's children, but at the same time we should be studying God's word to learn of Him and know Him. So I encourage you to ' study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth. ' 2Ti 2:15 Everything Jesus did was for a reason, everything that God instituted from the beginning is there for a reason as well. It all goes together, none of it will be left unfulfilled. Not one thing.
Blessings!