'Certain' in the Bible

This is the revelation of Jesus Christ [His unveiling of the divine mysteries], which God [the Father] gave to Him to show to His bond-servants (believers) the things which must soon take place [in their entirety]; and He sent and communicated it by His angel (divine messenger) to His bond-servant John,

Look! He is coming with the clouds,and every eye will see Him,including those who pierced Him.And all the families of the earthwill mourn over Him.This is certain. Amen.

I will cause some belonging to Satan's synagogue who say that they themselves are Jews, and are not, but are liars--I will make them come and fall at your feet and know for certain that I have loved you.

And to the angel of the church in Laodicea say: These things says the true and certain witness, the head of God's new order:

Here is wisdom. Let the person who has enough insight calculate the number of the beast, for it is the [imperfect] number of a man; and his number is six hundred and sixty-six.

And the heaven was open; and I saw a white horse, and he who was seated on it was named Certain and True; and he is judging and making war in righteousness.

And he who is seated on the high seat said, See, I make all things new. And he said, Put it in the book; for these words are certain and true.

And he said to me, These words are certain and true: and the Lord, the God of the spirits of the prophets, sent his angel to make clear to his servants the things which are now to come about.