I know some people, even Christians, who love to talk, but only about themselves. They'll tell you all about their interests and accomplishments (whether you inquire about such matters or not). Then, when you see them again, they'll continue to tell you more and more about themselves and their life. Those who are always talking--especially about themselves--will find it impossible to look out for the interests of others. To genuinely look out for the interests of others requires doing much listening and careful observing. It is difficult for a group of Christians to be like-minded when a member of the group is obsessed about himself and could not care less about others! Let us all labor to do better at looking out for the interests and well-being of others.
In 2:5-7, Paul wrote - "Let this mind be in you which was also in Christ Jesus, who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men." In these verses Paul continued exhorting Christians to be united. This is the fourth time he has used the word "let" in this immediate context. In essence, he has said: (1) let us not be selfish but humble, (2) let us consider others before ourselves, (3) let us look out for the interests of others, and ultimately (4) let us have the same mindset or attitude that Jesus had. If we can adopt the mindset of Christ, then we will be like-minded and united as God's children!
Well, if we're supposed to develop the attitude of Christ, what mindset did Jesus have? Paul begins to answer this question by talking about Jesus in His prior heavenly form, the form He had before He came to this earth as the Messiah. What form was that? The form of God! Jesus was and is divine. He was in the form of deity, like the Father and Holy Spirit. He was equal with the other members of the Godhead, and rightly so. However, as some footnotes (and the ASV) indicate, Jesus didn't consider His heavenly, divine form to be something that must be grasped or held onto in order to continue being equal with God. Jesus was willing to give up His heavenly form and take a different form upon Himself--the form of a bondservant or slave!
Please pause and really think about that--is this not amazing? We know that all things were created through Jesus Christ (cf. John 1:1-3,14). Think of the power and the glory of creating this universe and everything within it! Think of the awesome ability to speak things into existence and breathe life into non-living matter! Jesus had this power and glory in heaven! Jesus is divine, all-knowing, all-powerful, and everywhere! Why would He set aside the form He had in heaven--the form of God--and come down here to this planet to be a servant? Why would He empty Himself by leaving His glory in heaven? Why would He do it? Because of His awesome love! Jesus was humble; do you see that? The mind of Christ is the mind of humility. It's the mindset that isn't selfish but is willing to empty oneself and consider the needs of others first. It's the mindset that, if adopted by Christians, will lead to unity and like-mindedness.
Yes, "when the fullness of the time had come" (Gal. 4:4), Jesus left His heavenly home. He left that glorious form He had there and came to Earth as a servant of God to save man. He came in the "likeness of men." As John 1:14 says - He "became flesh and dwelt among us..." What a glorious thought! Are you working to develop the mind of Christ?