https://steve-finnell.blogspot.com/2016/11/musical-instruments-under-new-covenant.html
MUSICAL INSTRUMENTS UNDER THE NEW COVENANT? BY STEVE FINNELL
Did God authorize the use of musical
instruments under the New Covenant? Yes, He did. Not only did God
authorize musical instrument in the New Testament, He commanded them. He
also commanded we sing without instruments.
We are commanded to sing psalms. Colossians 3:16, Ephesians 5:19.
What is a psalm? Psalm 81:2 Raise a song, strike the timbrel, The sweet sounding lyre with the harp. (NASB)
PSALM DEFINED
1. Word Origin: Old English, from Late Latin psalmus. from Greek psalmos accompanied on the harp, from psallein to play (the harp) (Ref. Collins English Dictionary)
2. Primarily denoted a striking or twitching with the finger (on musical strings), then, a sacred song, sung to musical accompaniment, a psalm. (Ref. Vine's Expository Dictionary of Old and New Testament Words)
3. Word Origin and History for psalm: Old English psealm, salm, partly from Old French psaume, saume, partly from Church Latin psalmus, from Greek psalmos "song sung to a harp," originally "performance on stringed instrument; a plucking of a harp (cf. psaltes "harper"), from psallein "play on a stringed instrument, pull, twitch"
Used in Septuagint for Hebrew mizmor "song," especially the sort sung by David to the harp. Related: Psalmodize; psalmody.... (Ref. Online Etymology Dictionary, 2010 Douglas Harper)
4. Origin of Psalm: Middle English, from Old English psealm, from Late Latin psalmus, from Greek psalmos, literally, twanging of a harp. from psallein to pluck, play a stringed instrument. First Known Use: before 12th century. (REF. Merriam Webster)
God did not change the definition of the word psalm from the Old Testament to the New Testament. Psalm did not mean with musical instruments on 32 AD and then on the Day of Pentecost change to mean without instruments.
If God says it, it is His tradition. If men speak things that God did not, it is man-made tradition.
I believe worshipping with or without musical instruments is acceptable to God. It should never be a test of fellowship.