John Gill Commentary Psalms 150:3

"Praise him with trumpet sound: Praise him with psaltery and harp." — Psalms 150:3 (ASV)

Praise him with the sound of the trumpet
Which was used in calling the assembly together, for worship and on other occasions; and at the feast of blowing of trumpets, and in the year of jubilee, (Numbers 10:1Numbers 10:2) (Leviticus 23:23) (Leviticus 25:9Leviticus 25:10) ; and by the priests in temple service, (1 Chronicles 16:6 1 Chronicles 16:42) ; and was typical of the Gospel, which gives a certain and joyful sound, and is the cause and means of praising God, (Isaiah 27:13) ;

praise him with the psaltery ;
to which psalms were sung;

and harp ;
which were instruments of music, both used in divine worship under the former dispensation; and in which David was well skilled and delighted, and appointed proper persons to praise with them, (1 Chronicles 15:20 1 Chronicles 15:21) . They were typical of the spiritual melody made in the hearts of God's people, while they are praising him in psalms, hymns, and spiritual songs, under the Gospel, (Ephesians 5:19) (Revelation 5:2Revelation 5:8) (Revelation 14:2Revelation 14:3) .