bereft of God's grace, they shall be seized wherever they may be found, and slain one and all.

They shall have a curse on them: whenever they are found, they shall be seized and slain (without mercy).

Accursed, they will be seized wherever found and slain with a (fierce) slaughter.

Accursed, wherever they are found they will be seized and slain.

Accursed wherever they are found, [being] seized and massacred completely.