This verse reminds us that the world will hate us because we follow Jesus Christ. He warns us that we will face opposition and persecution for our faith. However, He also assures us that He has overcome the world and that we can have peace and joy in the midst of trials. He calls us to love one another as He has loved us, and to remain steadfast in our faith, even in the face of adversity. 
Christian faith has been regarded as false by unbelievers for many centuries due to the Person in whom our faith is based. Following many years of persecution, John warned us not to be surprised by the animosity that the world expresses towards believers. Instead, he encourages us to continue to show forgiveness, love, kindness, and grace to those who hate and revile us, just as he instructed us to pray for those who use us despitefully.
Although we are to live in this world as children of God, we are not to become a part of it, since we have been redeemed out of this world and have a heavenly inheritance that is kept in heavenly places for us. Let us walk in the light of Christ and not in the darkness of this world, and speak the truth in love to those of this world who are on the verge of perishing.

Dear Heavenly Father, I pray for the strength to face opposition and persecution for my faith in You. In spite of the fact that I may not be popular because I follow You, I find comfort in knowing that You have overcome the world. Grant me peace and joy in the midst of trials, and help me to love others as You have loved me. I trust in You, Lord, and ask for Your guidance in my life. Strengthen me to remain steadfast in my faith, even in the face of adversity. 
In Jesus's name I pray. Amen.