Unity is in Christ

…until we all reach unity in the faith and in the knowledge of God’s Son, growing into a mature man with a stature measured by Christ’s fullness. Then we will no longer be little children, tossed by the waves and blown around by every wind of teaching, by human cunning with cleverness in the techniques of deceit. But speaking the truth in love, let us grow in every way into Him who is the head—Christ. From Him the whole body, fitted and knit together by every supporting ligament, promotes the growth of the body for building up itself in love by the proper working of each individual part.
(Ephesians 4:13-16 Holman Christian Standard Bible ©®)

We will grow into having unity regarding doctrines (teachings) only to the degree that we have grown into Him Who is the head – Christ. Most believers are more interested in teachings about Christ than in Christ. Right teaching is very important. Right standing, unified in Christ, can give us access to it.