Compassion: The key to compassion is forgiveness of yourselves and all others

If you don't forgive yourself you cannot live. If you don't forgive others you cannot let them live either.

Understanding this seems a good way to stay alive if you want to.

 If you hate others you might kill them. If you hate yourself you might kill yourself.

So, in your own self interest of enlightenment and survival, you  must foster forgiveness of yourself and others. Otherwise, you and others might be dead. And even if it is others that are dead you likely will be arrested and put in jail or executed for killing others or harming others.

Forgiving yourselves and others therefore, is the way to stay alive to an old age even if you have to move somewhere else and start over more than once.

By God's Grace

This is the warriors stance of those who followed Saint Francis of Asisi who were trained as Warriors growing up. In this way they converted themselves from warriors to monks and holy people.

If you can convert to a holy person before you kill yourself or others this is much easier. Because PTSD is hard to deal with long term for most people.

Also, if you have PTSD try to convince others of the ways not to get PTSD from warlike situations.

By God's Grace

This is also how warriors become Holy Men and Holy Women.