Isaiah 26:3

1 In that day this song will be sung in the land of Judah: We have a strong city; salvation is established as its walls and ramparts.

2 Open the gates so a righteous nation may enter— one that remains faithful.

You will keep in perfect peace the steadfast of mind, because he trusts in You.

4 Trust in the LORD forever, because GOD the LORD is the Rock eternal.

5 For He has humbled those who dwell on high; He lays the lofty city low. He brings it down to the ground; He casts it into the dust.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
You will keep in perfect peace the steadfast of mind, because he trusts in You.
KJV
Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee.
WEB
You will keep whoever’s mind is steadfast in perfect peace, because he trusts in you.
ASV
Thou wilt keep [him] in perfect peace, [whose] mind [is] stayed [on thee]; because he trusteth in thee.
DARBY
Thou wilt keep in perfect peace the mind stayed [on thee], for he confideth in thee.
BLB
You will keep the one steadfast of mind in perfect peace, because he trusts in You.
ÅB
Den som har et grunnfestet sinn, ham lar du alltid ha fred, for til deg setter han sin lit.
OTB
Du vil holde i fullkommen fred de som har et stødig sinn, fordi de stoler på deg.
B1930
Den som har et grunnfestet sinn, ham lar du alltid ha fred, for til dig setter han sin lit.

Study notes (Tyndale)

Original text and word study

Cross references