1 Corinthians 3:2
I have fed you with milk, and not with meat: for hitherto ye were not able [to bear it], neither yet now are ye able.
Note 4 at 1Co 3:2: All of Paul's teaching about unity is not "deep" teaching, reserved for only the spiritually mature. He was saying this was "milk," not "meat." Therefore, those who think that unity among the believers is impossible because we are too immature are wrong. Paul made it very clear that these Corinthians were "babes in Christ" (see note 3 at 1Co 3:1), yet he commanded them to be of the same mind and judgment and to be perfectly joined together (see notes 1-2 at 1Co 1:10).