They have more immunity and powers, but they're able to’t make use of them on their own bash or other creatures (unless your DM says or else). Other abilities with the oath allow you to take damage for your allies, lessening the need for your party to spend actions and sources in combat

"At the present time the Lord will deliver you into my hand, and I will strike you down, and I will give the lifeless bodies with the host in the Philistines at the present time into the birds in the air and also to the wild beasts with the earth; that all of the earth may possibly know that Yo