“I still have 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, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come” (John 16:12–13).

Jesus did indeed have more to say. And indeed, He said it. To at least a highly significant extent, Jesus fulfilled His promise for more truth, more revelation, through the book of Revelation.

• “I still have many things to say to you”: “The revelation of Jesus Christ” (Rev 1:1).
• “He will declare to you the things that are to come”: “[T]o show to his servants the things that must soon take place” (Rev 1:1), “Write therefore the things […] that are to take place after this” (Rev 1:19).
• “When the Spirit […] comes, […] whatever he hears he will speak”: “He who has an ear, let him hear what the Spirit says to the churches” (Rev 2:7, 11, 17, 29; 3:6, 13, 22).
• “When the Spirit of truth comes, he will guide you into all the truth”: “These are the true words of God” (Rev 19:9), “these words are trustworthy and true” (Rev 21:5).

The book of Revelation is not optional reading in the Christian canon. It contains “many things” Jesus considered essential to teach His people regarding things to come.