What does “Mercy within mercy within mercy" mean?

I saw a lot of articles in these couple of days about Pope Francis’ reflection of his style, influences and priorities as pope in the recent interview with La Civilta Cattolica, the Jesuit journal in Rome.

In this interview, the words of Thomas Merton – “Mercy within mercy within mercy," was quoted, which appears in his book, “The Sign of Jonas” as follows:

"I have always overshadowed Jonas with My mercy, and cruelty I know not at all. Have you had sight of Me, Jonas My child? Mercy within mercy within mercy."

I understand it’s hard for non-Christian like me fully understand the meaning (Actually one of writers wrapped up his article by confessing he neither understand exact meaning of this phrase). But I would like to know at least basic implications of this phrase.

What does ‘within’ before ‘mercy’ represent for? If ‘within’ is replaced with ‘and’ with an aim at emphasizing, does it totally miss the point?

Solution 1:

It's describing God (I assume, judging from the capitalised Me), and using the analogy of an onion's layers.

If you take away the outer layer showing mercy, expecting to find cruelty underneath as the true nature, you don't: you find mercy. And if you scratch at that layer to get underneath, you find mercy again. He is mercy all the way through.

In this case, beauty is more than skin deep: it is the entire being.

Solution 2:

The statement is similar to Turtles all the way Down. Basically the speaker is saying he is all mercy, without a bit of cruelty. Not something you'd normally say about oneself, but for someone else, you might describe him as "without a cruel bone in his body".