Devotion to the cause of humanity?

"If our devotion is to the cause of humanity, we will be quickly defeated and broken-hearted, since we will often be confronted with a great deal of ingratitude from other people.  But if we are motivated by our love for God, no amount of ingratitude will be able to hinder us from serving one another... Once we realize that Jesus has served us even to the depths of our meagerness, our selfishness, and our sin, nothing we encounter from others will be able to exhaust our determination to serve others for His sake." 
-Oswald Chambers