It seems you are referencing John 16:12-13. Here we list in in full up to verse 16:
Jn.16:12 I have yet many [things] to be telling you, but you are not now able to be bearing [them]. 13 But when that [one] comes, the spirit of truth, he will guide you into all truth, for he will not speak from himself, but as much as he hears will he speak, and the coming [things] will he disclose to you.14 That [one] will glorify me, because he will receive from me and will disclose to you. 15 All as much as the father has is mine. Because of this I said that he receives from me and he discloses to you. 16 [A] little [while] and you no longer behold me, and again [a] little [while] and you will see me.
The Words of Jesus are sufficient and complete. We do not require others to come along as teachers to make up for what they think is lacking. There is nothing lacking in the Words of Jesus. He is Truth. He is our only Teacher. The Holy Spirit receives the Truth from Jesus, who receives it directly from the Father. The Holy Spirit does not require an intermediary. The only thing required is an open heart that is repentant and willing to hear and obey the Word.
We suggest the "coming things" that the Spirit would disclose to the disciples had to do with the purpose of Jesus' crucifixion, that is, his adherence to the Great Principle of hating his life in this world. Verse 12 reminds the disciples that they are not able to bear the things he wants them to understand. It will require his giving up of his life in this world followed by his resurrection for the disciples to understand.
I have yet many things to say to you, but you cannot bear them now. When the Spirit of truth comes, he will guide you into all the truth . . . (John 16: 12,13).