Commenting on this Psalm, Saint Augustine wrote:
We should not pass over the mysterious meaning of "tabret [tambourine] and harp" in silence. On a tambourine you have a skin stretched out, and in a stringed instrument you have catgut stretched out. So in both instruments ordinary flesh is being "crucified." The man who said, "The world is crucified to me and I to the world" (Gal 6.14) must have sung praises really well on this "tabret and harp!" And He Who loves a "new song" wants to take you to be that harp, that tabret. He gives you His instructions when He says, "Whoever wants to be My disciple, let him deny himself and take up his cross and follow Me." Do not let Him throw away His harp and His tabret. Let them be stretched out on wood [of the cross], and all fleshly desire dried out of them. Strings or sinews sound more sharply the more they are stretched out. And what does Paul the apostle say about making his harp sound more sharp and clear? "Forgetting what lies behind and straining forward to what lies ahead, I press on toward the goal for the prize of the upward call" (Phil 3.13-14). So he stretched himself out; Christ touched him, and the sweetness of truth gave tongue.
Saint Augustine, Discourses On The Psalms, Comments on Psalm 149.
Cited from Rowan Williams, Christian Spirituality (Atlanta: John Knox, 1979), 88.