What exactly is the meaning of Genesis 7:19-20?

Question

Does Genesis 7:19-20 say the flood was 15 cubits high or the water rose 15 cubits high from the bottom of the ark?

Genesis 7:19-20

And the waters prevailed exceedingly upon the earth; and all the high hills that were under the whole heaven were covered. Fifteen cubits upward did the waters prevail; and the mountains were covered” (KJV)

Answer 1

Most commentaries would say that the waters were 15 cubits above the tops of the mountains:

• Ellicott's Commentary for English Readers

  (20) Fifteen cubits upward.—This apparently was the draught of the ark, computed after it had settled. in the region of Ararat. Fifteen cubits would be about twenty-two feet, and as the ark floated onward without interruption until it finally grounded, there must have been this depth of water even on the highest summit in its course.

• Matthew Henry's Concise Commentary

  7:17-20 The flood was increasing forty days. The waters rose so high, that the tops of the highest mountains were overflowed more than twenty feet.

• Barnes' Notes on the Bible

  "Fifteen cubits upward." This was half the depth of the ark. It may have taken this draught of water to float it. If so, its grounding on a hill under water would indicate the depth of water on its summit.

• Jamieson-Fausset-Brown Bible Commentary

  20 Fifteen cubits upward … and the mountains were covered—twenty-two and a half feet above the summits of the highest hills.

• Gill's Exposition of the Entire Bible

  Fifteen cubits upwards did the waters prevail,.... Either to such an height above the earth, upwards from that, or from the high hills; for though the words do not necessarily imply that, yet it may be allowed, since there was water enough to cover the highest of them; and fifteen cubits of water were enough to drown the tallest man, or largest beast that should be upon the top of any of them:
  and the mountains were covered, with water, even it may be allowed fifteen cubits high;

• Cambridge Bible for Schools and Colleges

  20 Fifteen cubits] P describes a depth of water of 15 cubits (= 22 feet) above the mountains.

• Pulpit Commentary

  Verse 20. - Fifteen cubits upward - half the height of the ark - did the waters prevail. Literally, become strong; above the highest mountains obviously, and not above the ground simply; as, on the latter alternative, it could scarcely have been added, and the mountains were covered.

• Keil and Delitzsch Biblical Commentary on the Old Testament

  Genesis 7:17-24 contain a description of the flood: how the water increased more and more, till it was 15 cubits above all the lofty mountains of the earth, and how, on the one hand, it raised the ark above the earth and above the mountains, and, on the other, destroyed every living being upon the dry land, from man to cattle, creeping things, and birds.

• “All Scripture Is Inspired of God and Beneficial”: Bible Book Number 1—Genesis

  The downpour continues for 40 days, until even the tall mountains are covered by as much as 15 cubits (c. 22 ft) of water.