Numbers 10:7

Bible in Basic English 1965

But when all the people are to come together, the horn is to be sounded but not loudly.

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Let the horn be sounded in Zion, and a war-cry in my holy mountain; let all the people of the land be troubled: for the day of the Lord is coming;

The horns are to be sounded by the sons of Aaron, the priests; this is to be a law for you for ever, from generation to generation.