Luis de León and Isaiah 2:2
Luis de León (1527-1591) was an Augustinian friar, poet, and a Jesuit theologian. His book ‘The Names of Christ’ was written while he was imprisoned at Valladolid by the Spanish Inquisition from Mar. 1572 to Dec. 1576, while complaints by Dominican scholars about his use of the Hebrew text and the Septuagint in his lectures and writings were considered by the Inquisition. He was cleared of the charges and restored to his position.
In the paragraphs quoted below Luis discussed Isaiah’s prophecy in Isa. 2:2. He identified ‘the mountain of the Lord’s house’ with Christ. 
In the passage of Isaiah, in what precedes and in what follows, there is not a word which does not seem to designate precisely Christ. ‘In the last days,’ or as you know, the end of days, or the last days, are expressions in which Holy Scripture designate the epoch in which Christ is to come, as the prophecy of Jacob shows in Book of Creation (Gen. 49:1) and in other places. Because the epoch of His first coming, in which the light of the gospel began to be seen together with the Christ, is the period of the revolution of this light–which is that of his preaching, similar to a sun which makes its tour of the world and which passes from one nation to another–since the turning, the appearance, and the duration of this enlightenment is called a day; it is like the setting and rising of the sun in day, and this is called the last day since, once the course of the evangelical sun is ended–what it will have produced when it will have enlightened all the nations is similar to our sun–no other day will come to succeed it. Christ says, ‘And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come’ (Matt. 24:14).
He says also that ‘It will be established.’ The original word designates a foundation and installation free of change, not shaky or subject to the vicissitudes of time. The same is said in the Psalm (103:19) with the words ‘The Lord hath prepared his throne in the heavens.’ In fact, is there any other mountain or grandeur not subject to change than Christ’s alone, whose reign has no end, as the Angel told the Virgin? (Luke 1:32) Now, what do we read? ‘The mountain of the house of the Lord.’ This excellent house among all the others is Christ our redeemer, in whom God rests and lives eternally as it is written. ‘For in him dwelleth all the fulness of the Godhead bodily.’ The text says, ‘above the summit of the mountains,’ something which can be said only of Christ. In fact, ‘the mountain’ in Scripture and in the secret manner of speaking which Holy Scripture employs designating all that is eminent, either in earthly power, such as princes, or in virtue and spiritual knowledge, such as the prophets and the prelates. And to say ‘mountains’ without limitation is to say all mountains (as that is understood from an article which is in the primitive text), that is, ‘the most remarkable of all the mountains’ as much by their height as by their other qualities and characteristics. To say that He will be established on ‘all the mountains’ is not to say that the mountain is raised higher than the others but that it is placed on the summit of all, so that its lowest part is above what among others is the highest.
Isaiah’s prophecy came to pass when Jesus was exalted to his Father’s throne in heaven, after he was raised from the dead, and the prophecy continues to be fulfilled as people from the nations are enlightened with the light of the gospel and come into the church.
Luis explained further the meaning of Christ being called ‘mountain.’ 
First of all, let us say what it means to call Christ ‘mountain.’ Then we will return to these same passages and we will express some characteristic words which the Holy Spirit attributes to this mountain. I will say this: Beyond what these mountains possess over the rest of the land–that is, a superiority as remarkable as that of the Christ, as man has above all other creatures–the principal reason for which Christ is called mountain is the abundance or the plenitude and riches of different goods which He has amassed and which He bears in Himself. Thus we know in Hebrew, a language in which the sacred books are in their original state, the word which designates mountain, in its proper sense, designates in our language ‘he who is full’ so that what we call ‘mountains’ is called properly ‘full’ in Hebrew.
Another reason Christ is represented by a mountain is that mountains represent promises, [Gen. 49:26] and Jesus is the seed promised to Abraham in whom all nations will be blessed.
1. Luis de León. The Names of Christ. Tr. by Manuel Durán, William Kluback. Paulist Press, 1984. pp. 103-104.
2. Ibid., p. 106.