Is it worth it to stand by someone other than yourself? Fight for someone other than yourself? Actually, carry someone else’s burdens?

Absolutely! You will receive your reward, in due time.

Galatians 6:2, 9 (KJV) – bear ye one another’s burdens, and so fulfil the law of Christ. And let us not be weary in well doing: for in due season we shall reap, if we faint not.