What are the differences between, "saith" and, "said", in these last two chapters of the Bible?

Revelation 21:5 And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful.

  6 And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely.

Revelation 22:6 And he said unto me, These sayings are faithful and true: and the Lord God of the holy prophets sent his angel to shew unto his servants the things which must shortly be done.

  9 Then saith he unto me, See thou do it not: for I am thy fellowservant, and of thy brethren the prophets, and of them which keep the sayings of this book: worship God.

  10 And he saith unto me, Seal not the sayings of the prophecy of this book: for the time is at hand.

  20 He which testifieth these things saith, Surely I come quickly. Amen. Even so, come, Lord Jesus.

Is, "said", simply past tense of, "to say", whereas, is, "saith", present tense, or an ongoing tense?

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