Explanation: In Abrahamic mythology, the core religious figure of Abraham, for no other reason than that YHWH instructed him to, bound his young child, Isaac, and prepared to sacrifice him. At the last moment, YHWH revealed it was only a test of his faith.

In Roman history, during the Early-Mid Republic, Consuls (who served as both generals and civilian leaders) Publius Decius Mus and Titus Manlius Torquatus mutually agreed during the Latin War (Romans were Latin-speakers, but Latins were filthy, neighboring Italians that committed the crime of being slightly different than them, and thus were barbaric) that if either wing of the army began to falter, the consul on that wing would perform devotio, an old ritual of self-sacrifice, in which the one performing the rite dedicated themselves to the gods of the underworld in exchange for victory in battle.

Mus's wing faltered first, so he called upon the high priest, performed the ritual (it was relatively brief, a little movement of the toga and some presumably-loudly-pronounced ritual words), and then, to fulfill the sacrifice portion of the ritual, charged in full armor, alone, into the mass of advancing Latin troops, killing several of them and fighting with such fury that they were too terrified to meet him in melee (supposedly). A javelin eventually killed him.

Upon seeing this, the Romans swept forward, assured by their belief in the validity of their general's sacrifice, and filling the gap created by the crazed death-seeking charge of Consul Mus, managed to rout the Latins entirely, leading to a Roman victory in the battle.

The ritual, for those interested:

The Pontifex bade him veil his head in his toga praetexta, and rest his hand, covered with the toga, against his chin, then standing upon a spear to say these words: "Janus, Jupiter, Father Mars, Quirinus, Bellona, Lares, ye Novensiles and Indigetes, deities to whom belongs the power over us and over our foes, and ye, too, Divine Manes [ancestor spirits], I pray to you, I do you reverence, I crave your grace and favour that you will bless the Roman People, the Quirites, with power and victory, and visit the enemies of the Roman People, the Quirites [citizens], with fear and dread and death. In like manner as I have uttered this prayer so do I now on behalf of the commonwealth of the Quirites, on behalf of the army, the legions, the auxiliaries of the Roman People, the Quirites, devote the legions and auxiliaries of the enemy, together with myself to the Divine Manes and to Earth."

Fascinating!