Isaiah 26:3 in the World English Bible
You will keep whoever’s mind is steadfast in perfect peace, because he trusts in you.
Context
2 Open ye the gates, that the righteous nation which keepeth the truth may enter in.
3 Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee.
4 Trust ye in the LORD for ever: for in the LORD JEHOVAH is everlasting strength: