The Bible says we are to love God above all else. And next to that love is the horizontal one, yourself on the right and others on the left. It should be equal. Don't love yourself more or less than others and vice versa. There are times that we tend to cross that thin line of loving either one side more than the other side. God said in John 15 that we are to attain the balance.
Bieber's song was sarcastically designed with the words that may not sound really pleasing. But it's a reality. A person may just trample your pure love on the ground and then you will just later move on. Moving on is quite hard. It's very critical. But when you finish that process, you will realize that the freedom you have gained is actually a gift. Being a prisoner of the wrong love is a total torment. And being free from such torment is bliss.
With this song I thought that people who are in the wrong relationship should not just change the object of his or her love. He or she should also change himself or herself.
On another note, I pray that Bieber continues his journey to change for the glory of God. I also pray for myself and the whole world to know God better and understand the real meaning of love through His Son Jesus Christ.