How do you get Spear of the Prophet with the console?

effect create_artifact_spear_of_the_prophet_effect = { OWNER = root } — runs the scripted effect that makes it, for the character you play (debug mode).

What if the owner can't benefit from Spear of the Prophet?

They get Court grandeur baseline +3 instead.

Court artifact · Pedestal Item

Spear of the Prophet

IllustriousUniqueHoly relicThe Royal Court

Spear of the Prophet is an illustrious pedestal item artifact in Crusader Kings III: Court grandeur baseline +6, Monthly Piety per Knight +3%, Levy Reinforcement Rate (Same Faith) +50%, Clan Ruler of Same Faith Opinion +5, Knight Effectiveness +20%. Quality 100 and wealth 100; maximum durability 150, and it does not wear out. At game start it goes to the holder of Sunni Caliphate — needs The Royal Court. It needs The Royal Court. Patch 1.20.0.3, from game/common/scripted_effects/01_exp1_historical_artifacts_creation_effect.txt.

Quick answers (3)

What does Spear of the Prophet do in CK3?: Court grandeur baseline +6, Monthly Piety per Knight +3%, Levy Reinforcement Rate (Same Faith) +50%, Clan Ruler of Same Faith Opinion +5, Knight Effectiveness +20% (patch 1.20.0.3).
How do you get Spear of the Prophet with the console?: effect create_artifact_spear_of_the_prophet_effect = { OWNER = root } — runs the scripted effect that makes it, for the character you play (debug mode).
What if the owner can't benefit from Spear of the Prophet?: They get Court grandeur baseline +3 instead.

Reportedly, the Spear of Muhammad, brought as a gift by the ruler of Abyssinia to al-Zubayr bin al-Awwam.

Effects

For an owner who can't benefit from it

The template gives these instead of the effects above when its “can benefit” check fails:

Court grandeur baseline+3

Who can benefit (can_benefit) (1 line of game script)

islamic_artifact_access_trigger = yes

As written in game/common/artifacts/templates (islam_artifact_template).

Counts as a holy relic for (is_holy_relic) (6 lines of game script)

OR = {
	religion = religion:islam_religion
	main_rite = {
		rite_has_parameter = islamic_syncretic_actor
	}
}

As written in game/common/artifacts/templates (islam_artifact_template).

History and who has it

Made before recorded history.
At game start: the holder of Sunni Caliphate — needs The Royal Court.

How it is made

The game creates it with the scripted effect create_artifact_spear_of_the_prophet_effect. In the console (how to open it), this gives it to the character you play:

effect create_artifact_spear_of_the_prophet_effect = { OWNER = root }

Built from the effect's file; not run in the game by us.

Source: game/common/scripted_effects/01_exp1_historical_artifacts_creation_effect.txt, common/modifiers (spear_prophet_modifier), common/artifacts/templates (islam_artifact_template) and the English localisation, Crusader Kings III 1.20.0.3.