30 beware that you are not ensnared to follow them, after they are destroyed before you, and that you do not inquire after their gods, saying, 'How do these nations serve their gods, that I also may do likewise?' 31 "You shall not behave thus toward the LORD your God, for every abominable act which the LORD hates they have done for their gods; for they even burn their sons and daughters in the fire to their gods. 32 "Whatever I command you, you shall be careful to do; you shall not add to nor take away from it.

Deuteronomy 12:30-32 (emphases added)

25 He then stationed the Levites in the house of the LORD with cymbals, with harps, and with lyres, according to the command of David and of Gad the king's seer, and of Nathan the prophet; for the command was from the LORD through His prophets. 26 And the Levites stood with the musical instruments of David, and the priests with the trumpets. 27 Then Hezekiah gave the order to offer the burnt offering on the altar. When the burnt offering began, the song to the LORD also began with the trumpets, accompanied by the instruments of David, king of Israel. 28 While the whole assembly worshiped, the singers also sang and the trumpets sounded; all this continued until the burnt offering was finished. 29 Now at the completion of the burnt offerings, the king and all who were present with him bowed down and worshiped. 30 Moreover, King Hezekiah and the officials ordered the Levites to sing praises to the LORD with the words of David and Asaph the seer. So they sang praises with joy, and bowed down and worshiped.

2 Chronicles 29:25-30 (emphases added)

22 And Chenaniah, chief of the Levites, was in charge of the singing; he gave instruction in singing because he was skillful.

1 Chronicles 15:22

Sing to Him a new song; Play skillfully with a shout of joy.

Psalm 33:3

30 Moreover, King Hezekiah and the officials ordered the Levites to sing praises to the LORD with the words of David and Asaph the seer. So they sang praises with joy, and bowed down and worshiped.

2 Chronicles 29:30

23 Therefore it was necessary for the copies of the things in the heavens to be cleansed with these, but the heavenly things themselves with better sacrifices than these. 24 For Christ did not enter a holy place made with hands, a mere copy of the true one, but into heaven itself, now to appear in the presence of God for us;

Hebrews 9:23,24 (see chapters 8-10)

16 "This is the covenant that I will make with them After those days, says the Lord: I will put My laws upon their heart, And upon their mind I will write them," He then says, 17 "And their sins and their lawless deeds I will remember no more." 18 Now where there is forgiveness of these things, there is no longer any offering for sin.

Hebrews 10:16-18 (see 2 Chronicles 29:25-30)

18 And do not get drunk with wine, for that is dissipation, but be filled with the Spirit, 19 speaking to one another in psalms and hymns and spiritual songs, singing and making melody with your heart to the Lord; 20 always giving thanks for all things in the name of our Lord Jesus Christ to God, even the Father; 21 and be subject to one another in the fear of Christ.

Ephesians 5:18-21

27 And when He had taken a cup and given thanks, He gave it to them, saying, "Drink from it, all of you; 28 for this is My blood of the covenant, which is poured out for many for forgiveness of sins. 29 "But I say to you, I will not drink of this fruit of the vine from now on until that day when I drink it new with you in My Father's kingdom." 30 And after singing a hymn, they went out to the Mount of Olives.

Matthew 26:27-30

9 But you are a chosen race, a royal priesthood, a holy nation, a people for God's own possession, that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light;

1 Peter 2:9

Note: Levitical singers were assistants to the priests; i.e., if priests, then Levites; if Levites, then singers (Aaron & priests were from the tribe of Levi)