What inspires warriors to make a such personal sacrifices?

It deppends on the type of warrior but I will try to explain using the Samurai. I think with them the value of the moral is of high importance and determined their lives:

The samurai considered death as something they had to be always prepared for and thus, whenever it was needed, they would sacrifice their life "for a greater good" they knew it was something it might happen anyway. The idea of trascendence is something we have to be also aware of; They thought that what you do in this life will affect how you start the next one (reincarnation).

Let's also talk about a "negative" way of sacrifice; The seppuku, where they took their own life by cutting their stomach with a sword when they considered they didn't follow properly one of the eight most important values as we can see in any of the samurai codes or books like Hagakure or the Bushido code. these eight codes are: Justice, courage, mercy, politeness, honesty, honor, loyalty and self-control.

Not only life they would sacrifice but also money, food, social life because these things might be a distraction or a cause of desire whic leads to suffering.