John 16:12

12. Many things to say… ye cannot bear The wise teacher knows not only how to instruct, but how to withhold instruction that he may instruct in the right order. He will not impose truths upon brains not strong enough to bear them. And some instructions need diagrams, examples, apparatus, or experiments before they can be understood. So these apostles needed that Christ should suffer, rise, and be glorified before they could understand and preach a suffering, risen, and glorified Saviour. Nor were they as yet prepared to accept in heart the abolishment of circumcision and of the Jewish ritual, with the destruction of Jerusalem, the overthrow of the Jewish state, and the reduction of Jew and Gentile into one universal Christian Church. Much he probably taught them during the forty days after his resurrection; but, as the next verse teaches us, it required the coming of the Spirit fully to graduate them into a competent apostleship.