Psallō appears 5 times in the NT (Romans 15:9; 1 Corinthians 14:15; Ephesians 5:19; James 5:13; and possibly in Paul's letters). Originally meaning 'to pluck or twitch strings' (of a harp, lyre, or lute), it came to mean 'to sing while playing,' and then 'to sing sacred songs, sing psalms.' In Paul's instruction on worship (1 Corinthians 14:15), he says he will pray and psallō both 'with my spirit' and 'with my mind' — indicating that musical praise should be both heartfelt and intelligible.
The practice of psallō — singing praise — is presented in the NT as a universal Christian activity, not merely for specialists. James 5:13 asks: 'Is anyone happy? Let them sing songs of praise [psalletō].' Paul's instruction to 'speak to one another with psalms, hymns, and spiritual songs, singing [adontes] and making music [psallontes] from your heart to the Lord' (Ephesians 5:19) uses psallō for the heart-directed, instrumental/vocal dimension of praise. The early church was a singing community — their songs were both a form of worship and a vehicle for theological formation. Communal praise expressed in song remains a distinctive mark of Christian community.