Because it sums up the major beliefs of Judaism.

Im pretty sure his name is Matishyahu

While some prayers may be found in the Tanakh (Hebrew Bible) and in the Talmud, the complete text of Jewish worship is in the Siddur (Jewish prayerbook). The earliest parts of the Siddur were composed some 2350 years ago by the sages of that time; and the most recent prayers (such as Lekha Dodi, Adon Olam and Yigdal) were added to the Siddur around 500 years ago.

Judaism is far more about practice than belief, and aside from "Hear oh Israel, the Lord your God, the Lord is One," Jews have not struggled over the issue of articles of faith. In the 12th century, Rabbi Moses ben Maimon, known by his Latinized name Maimonides, responded to the interaction of Jews with Christianity and Islam by listing 13 articles of faith. His list is the basis of the popular him Yigdal. The articles he listed were: God exists, is one and unique, incorporeal, eternal, is the only object of prayer, the prophets spoke truth, Moses was the greatest prophet, the Written and Oral Torah were given to Moses, there will be no other Torah, God knows our thoughts and deeds, God rewards good and punishes evil, the Messiah will come and the dead will be resurrected.

First, Judaism is far more action centered than belief centered. So one belief you could list is "actions matter more than words." Unlike Christianity, Jews are not big on statements of creed, but one statement is repeated twice daily, the Shema, Deuteronomy 6:4: Hear oh Israel, the Lord your God, the Lord is One. So, another belief you could list is the oneness of God. Close to 1000 years ago, Moses Maimonides wrote out a creed, his 13 principles. These make a great hymn, Yigdal. In short, they are that God is the creator, is one, is incorporeal, is eternal, is the only object of worship, and communicates with man through prophets; Moses was the greatest prophet; the Torah is the word of God, and is immutable; God is omniscient, punishes sin/rewards righteousness, and will send the messiah.