Psalm Codes are one of the items (alongside Archeotech Shards) that you can place into your empty sockets (essentially "gems" in other games).

You can find more info on what each Psalm Code does and their rarity in the official Compendium: https://neocoregames.com/en/community/warhammer-40k-inquisitor-martyr-compendium#section-psalm-codes

When you reach Level 20, items can start to drop with sockets. You can freely add and remove Psalm Codes to these sockets. You can even stick the same Psalm Code in all the sockets.

When you equip a certain combination of Psalm Codes, it is called a Psalm Code Doctrine.

The number of Psalm Codes required to form a Doctrine can range between 3-6. You need the corresponding number of sockets on an item to gain the Doctrine effect.

You can see the Psalm Code combinations to create Doctrines and Doctrine effects in the official compendium: https://neocoregames.com/en/community/warhammer-40k-inquisitor-martyr-compendium#section-psalm-code-doctrines

Simply place the required Psalm Codes on a single item to gain the Doctrine's effect.


When gaining the effect of the Doctrine, you also keep the individual effect of the Psalm Codes. See the above and below image for reference.

When attempting to gain the Doctrine effect, you cannot split the required Psalm Codes across multiple items. This means if you have a 6 combo Doctrine, you cannot place the Psalm Codes in a 3 socket item. For example, If you try to split them into a 2 socket item and 4 socket item, you will gain the individual Psalm Code effects but not the Doctrine effect. If you do, you will find it's fairly obvious it won't work, as the Doctrine effect won't appear on the item.

If you have a 6 socket item, and place 2x 3 combo doctrines, only the first one will gain the Doctrine effect. However, the effects of all 6 individual Psalm Codes will still be there.