Two ideas sit next to each other in the verse: (1) Yahweh distinguishes and claims a certain person (“for himself”), and (2) that relationship grounds confidence in prayer being heard. The text explicitly presents this as more than the speaker’s optimism; it is framed as something others must recognize.

Where interpretation differs

Some differences come from the key terms.

Who is addressed by “know.” Many read the command as aimed at the same opponents addressed just before (“sons of men”), but the verse itself does not name them.

What “godly” means. The word can point to loyal, devoted, covenant-faithful character. Some take it mainly as moral seriousness; others stress loyal love toward Yahweh and faithfulness within the covenant community.

What “set apart” implies. Some understand it primarily as protective belonging (Yahweh marks the faithful as his own). Others also hear a public or vocational note: Yahweh distinguishes the speaker in a way that undercuts the opponents’ claims.

What “hear” entails. Some take “hear” as “pay attention to,” without specifying the outcome. Others take it as “hear and answer,” meaning Yahweh will act in response.

Why the disagreement exists The verse is short and uses relational verbs rather than detailed explanation. “Godly,” “set apart,” and “hear” are meaningful but broad, and Psalm 4 does not spell out the exact situation (slander? political rivalry? temple dispute?). That leaves room for readers to weigh context clues differently—especially whether the line is mainly about personal piety, public vindication, or both.

What this passage clearly contributes This verse clearly links belonging to Yahweh (“set apart for himself”) with confidence that prayer is not ignored (“Yahweh will hear when I call”). It presents Yahweh as one who makes distinctions within the community—recognizing and claiming the faithful—and as one who is responsive to their cry. The speaker treats this as a public truth meant to challenge opponents’ assumptions, not merely a private feeling. Key terms that carry the meaning include godly and the idea of being set apart.

godly (ḥā·sîḏ)