Cerenthi et Phelethi (Cerenthi and Phelethi) were the peoples that David sent out in pursuit of Sheba in 2 Samuel 20.

2 Samuel 20:6-8... "And David said to Abisai: Now will Seba the son of Bochri do us more harm than did Absalom: take thou therefore the servants of thy lord, and pursue after him, lest he find fenced cities, and escape us. 7So Joab's men went out with him, and the Cerethi and the Phelethi: and all the valiant men went out of Jerusalem to pursue after Seba the son of Bochri." (Douay-Rheims Bible)

From 1 Chronicles 25:

1 Moreover David and the captains of the host separated to the service of the sons of Asaph, and of Heman, and of Jeduthun, who should prophesy with harps, with psalteries, and with cymbals: and the number of the workmen according to their service was:

2 Of the sons of Asaph; Zaccur, and Joseph, and Nethaniah, and Asarelah, the sons of Asaph under the hands of Asaph, which prophesied according to the order of the king.

3 Of Jeduthun: the sons of Jeduthun; Gedaliah, and Zeri, and Jeshaiah, Hashabiah, and Mattithiah, six, under the hands of their father Jeduthun, who prophesied with a harp, to give thanks and to praise the LORD.

4 Of Heman: the sons of Heman; Bukkiah, Mattaniah, Uzziel, Shebuel, and Jerimoth, Hananiah, Hanani, Eliathah, Giddalti, and Romamtiezer, Joshbekashah, Mallothi, Hothir, and Mahazioth:

5 All these were the sons of Heman the king's seer in the words of God, to lift up the horn. And God gave to Heman fourteen* sons and three daughters.

Asaph was a Levite singer, prophet, and seer who served during the reigns of David and Solomon. He was a descendant of Gershon, the son of Levi, and was appointed by David to lead the music service in the house of Yahweh. Asaph is credited with composing Psalms 50, 73, 76, and 78, and may have also composed Psalms 75, 77, and 82. He is also mentioned in 2 Chronicles 5:12 as performing at the dedication of Solomon's temple.

Ethan or Aethan was a boy at King David's court well known for his wisdom. He authored Psalms 89

Eman or Aeman or Heman the Ezrahite is the author of Psalm 88. He is mentioned in 1 Chronicles 25:

Jeduthun or Idithun was one of the three masters of music appointed by David, generally to preside over the music of the temple service. Jeduthun's name stands at the head of Psalms 39, 62 and 77.

On the four corners looking in are the Four Cardinal Virtues:

prudence ( Latin: prudentia or prydentia)

justice ( Latin: iustitia)

temperance ( Latin: temperantia)

courage ( Latin: fortitudo).