Feast of Trumpets
(The trumpet was Israel's means of communication. see Num 10:1-10 To assemble the people, trumpets were blown. They were blown as 'officer's call,' just as in the military, to cause this or that tribe to march, or to herald the arrival of special occasions. They were blown as an announcement, or they were blown as an alarm if an enemy was approaching, and blown on solemn holy days.)
1 Cor 15:50-52 "Now this I say, brethren that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption. Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed. 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."
(The primary focus of the Feast of Trumpets is the return of Jesus Christ to this earth.)
(The emphasis on the Feast of Trumpets is mostly prophetic! It focuses mainly on Christ's coming and the resurrection, but also foreshadows the announcement God is sending to mankind through the preaching of the Gospel of Christ as a witness and a warning.)
Funk and Wagnall Encyclopedia -Shofar "musical instrument developed by the ancient Hebrews and consisting of an antelope's or ram's horn, with the smaller end flattened to form a mouthpiece. The shofar can produce only two tones; thus, as a purely musical instrument, it is very limited. In ancient times it was used as a signaling instrument in various cultic ceremonies and rituals, most notably in the Temple. The shofar is still used by Jews in the rituals celebrating Rosh Hashanah and Yom Kippur."