1 Corinthians 1:10
I appeal to you, brothers and sisters, in the name of our Lord Jesus Christ, that all of you agree with one another in what you say and that there be no divisions among you, but that you be perfectly united in mind and thought.
This verse encapsulates the whole of the first Corinthian letter. Jesus prayed for the disciples to be united-to the point of complete unity (John 17:23). Unity is powerful. Disunity is powerless. The Corinthians Church lacked no spiritual gifts or spiritual mentors yet deficient of true spiritual power to live for God. They had the best orators of their day teaching them the way of truth but were considered infants in Christ (1 Corinthians 3:1). It was a pity that although they were enriched in many ways, they failed to enrich one another. Although they were blessed beyond measure, they failed to notice the grace of God working in their lives.
At the root of divisions lies the great SiN called "I." Paul had to remind them to seek for the common good of others and not of selfish interest. To seek someone's else' interest is to give up one's own in many ways. In that, it involves humility and tearing out one's own pride. How do we do that? In the name of our Lord Jesus Christ. Look to Christ and see his example of kenosis "act of self-emptying" who took upon the nature of a servant,... (Phil 2:7).
The reason that Jesus and Paul calls for unity is because it has the power to show what the world lacks. The world is divided based on race, gender, color, caste, and creed but God calls for Christians to unite so that God's power and name will be glorified through His Church.
Prayer: Holy Father, as you are one with Jesus and the Holy Spirit, unite your Church in this one Spirit to to testify and glorify your name, amen.