Here is a verse that shows us how Jesus lived on earth as a Man: "You have loved righteousness and hated lawlessness. Therefore God, Your God has anointed You with the oil of gladness above Your companions" (Hebrews1:9). When Jesus lived on earth, He lived with all the limitations of us human beings. So He needed to be anointed. God the Father doesn't need to be anointed. And Jesus did not need to be anointed when He was in heaven. But when He lived on earth, He had to be anointed to be an Example for us. Here in this verse we are told why God anointed Jesus with the oil of gladness (joy) more than us, His companions. It was primarily because of one reason - He loved righteousness and hated lawlessness. He loved purity and hated sin.
There is a difference between doing righteousness and loving righteousness. A child can obey his father without loving to obey. Jesus did not just do righteousness, He loved righteousness. In the same way, Jesus did not just avoid sin. He hated sin. AIDS is one of the deadly diseases that people get through sexual sin nowadays. And so, many don't commit fornication because of the fear of getting AIDS. They don't hate sexual sin; they are just afraid of getting AIDS. In the same way many who want to steal don't do so, because they are afraid they might get caught - not because they hate stealing. In the same way, you can avoid any other sin without hating it. But if you want to be anointed with the oil of gladness, you have to love righteousness and hate sin. It says here that that was the reason why Jesus was anointed with the oil of gladness more than others.
There is no partiality with God. A good father will never treat his eldest son with greater favour than his other children - there will be no partiality with him. What he does for his eldest son he will do for all his children. God the Father is also like that. Jesus is called the First-born of many brothers. We who are born again are His younger brothers. Jesus is the Eldest Son. Since God is not partial, He will do everything for us that He did for His Eldest Son, Jesus. Whatever God did for Jesus, He will do for me too, if I fulfil the same conditions that Jesus fulfilled. This is one of the great truths that we discover through knowing about the humanity of Christ.
If it had been written that Jesus was anointed with the oil of gladness because He was the Son of God that would not have encouraged or challenged us in any way. But when we read that He was anointed because He loved righteousness and hated lawlessness that gives us hope that we can be anointed in the same way too, if we also love righteousness and hate sin. So we need to pray, "Lord, work in my heart through the Holy Spirit, so that I will not only do righteousness but love it; and that I will not only avoid sin but hate it."
The more we love righteousness and the more we hate sin in our lives, the more we will be filled with the joy of the Holy Spirit. The kingdom of God which is righteousness and joy in the Holy Spirit will come and fill our hearts (Romans 14:17). Then we will be enabled to obey the command that tells us to "rejoice in the Lord ALWAYS" (Philippians 4:4).