Found in Phillipians Chapter 2. One of my favorite sections of scripture. Paul was writing to the church in Phillipi regarding their inability it seemed to work together. Starting with verse 2: "Make my joy complete by being of the same mind, maintaining the same love, united in spirit, intent on one purpose. Do nothing from selfishness or empty conceit, but with humility of mind regard one another as more important than yourselves; do not merely look out for your own personal interests, but also for the interest of others. Have this attitude in yourselves which was also in Christ Jesus..... who emptied Himself.... the form of a bond-servant.... humbled Himself.... by becoming obedient to the point of death, even death on a cross."
And then, in verse 14, Paul lays the smack down again- "do all things without grumbling or disputing; so that you will prove yourselves to be blameless and innocent.... children of God."
As leaders, it is our responsibility to model this. Quit griping, grumbling, disputing, and arguing, and start leading, serving, encouraging, and uniting.
The book of Phillipians has so much great stuff on unity, teamwork, and servant leadership. A good reminder as we lead up to Easter this weekend.