This scripture emphasizes unity among Christians: “like-minded,” “one mind,” and “one mouth”. It also gives the basis for that unity, “according to Christ Jesus.” The Weymouth translation says, “in accordance with the example of Christ Jesus.” The Bible in Basic English says, “in harmony with Christ Jesus.”

The foundation of Christian unity is that we are trying to be in harmony with Jesus. “Let this mind be in you which was also in Christ Jesus.” (Philippians 2:5) As we strive to be like Christ, we have closer fellowship with those who are doing the same. 

Jesus tells us he is the “light of the world and he that follows me shall not walk in darkness, but shall have the light of life.” (John 8:12) 

A common misconception about unity is that it is the acceptance and tolerance of every idea as Christian. The Apostle John explains “If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth: But if we walk in the light, as he is in the light, we have fellowship one with another,” 1 John 1:6-7.  He is making a contrast between “walking in darkness” and “walking in the light.” Our fellowship with one another is based on “light” or enlightenment.

What does it mean to “walk in the light” and avoid darkness? All teachings of doctrine and practice need to be supported by scripture. “To the law and to the testimony! If they do not speak according to this word, it is because there is no light in them.” (Isaiah 8:20) 

John further teaches, “believe not every spirit but try the spirits whether they are of God; because many false prophets are gone out into the world.” (1 John 4:1)

There should be a contrast between what Christians believe and live as compared to what the world believes and practices. “For you were once darkness, but now you are light in the Lord. Walk as children of light (for the fruit of the Spirit is in all goodness, righteousness, and truth), finding out what is acceptable to the Lord. And have no fellowship with the unfruitful works of darkness, but rather expose them (as error).” (Ephesians 5:8-11) ​

True Christian unity is based on “goodness, righteousness, and truth.” (Ephesians 5:9)