'Seal Up' in the Bible

He has also set his seal upon me, and given me the pledge of his Spirit in my heart.

When the seven thunders uttered their voices, I was about to write; but I heard a voice from the sky, saying, "Seal up the words which the seven thunders uttered, and write them not."

And he said to me, "Do not seal up the words of the prophecy of this book; for the crisis is near.