'Seal Up' in the Bible

Set me as a seal upon your heart, as a seal upon your arm; for love [is] strong as death; passion [is] fierce as Sheol; its flashes [are] flashes of fire; [it is] a blazing flame.

And when the seven thunders spoke, I was about to write, and I heard a voice from heaven saying, "Seal up [the things] which the seven thunders spoke, and do not write them!"

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