Shared ground
Psalm 150:3 gives two parallel lines that say the same basic thing twice: “Praise him … Praise him …,” then names instruments as the means. The text’s explicit claim is not about why God should be praised (that was already stated earlier in the psalm), but that praise may be expressed in concrete, audible ways.
The “trumpet” is presented as a loud, attention-getting sound (“sounding/blast”), fitting public, gathered praise. “Harp and lyre” (string instruments) add a different kind of musical voice—melody and accompaniment—so the verse pictures praise as both piercing and rich, not confined to one sound.
Where interpretation differs (only where needed)
Some readers take the instrument list as a direct, ongoing pattern for worship gatherings: the verse commends using recognized instruments to support communal praise.
Others treat the list as representative rather than prescriptive: the point is the fullness and variety of praise, not that these particular instruments must be present.
Why the disagreement exists
The verse is a series of commands tied to specific instruments, which can sound like a blueprint. At the same time, Psalm 150 as a whole rapidly “piles up” examples to create a crescendo, which can suggest the instruments function as an expanding illustration of energetic praise rather than a strict requirement.
What this passage clearly contributes
This verse clearly contributes that praising God can rightly be public and audible, including strong signals (trumpet blast) and skilled musical accompaniment (harp and lyre). It also contributes an image of praise that is varied and abundant, reinforced by the repeated “Praise him” and multiple instruments (see Psalm 150:1–6).
