Explains how this secret wisdom is likewise a ladder.
IT now remains to consider the second point–namely, how this secret wisdom is likewise a ladder. With respect to this it must be known that we can call this secret contemplation a ladder for many reasons. In the first place, because, just as men mount by means of ladders and climb up to possessions and treasures and things that are in strong places, even so also, by means of this secret contemplation, without knowing how, the soul ascends and climbs up to a knowledge and possession of  the good things and treasures of Heaven. This is well expressed by the royal prophet David, when he says: Blessed is he that hath Thy favour and help, for such a man hath placed in his heart ascensions into the vale of tears in the place which he hath appointed; for after this manner the Lord of the law shall give blessing, and they shall go from virtue to virtue as from step to step, and the God of gods shall be seen in Sion.’  This God is the treasure of the strong place of Sion, which is happiness.
2. We may also call it a ladder because, even as the ladder has those same steps in order that men may mount, it has them also that they may descend; even so is it likewise with this secret contemplation, for those same communications which it causes in the soul raise it up to God, yet humble it with respect to itself. For communications which are indeed of God have this property, that they humble the soul and at the same time exalt it. For, upon this road, to go down is to go up, and to go up, to go down, for he that humbles himself is exalted and he that exalts himself is humbled.  And besides the fact that the virtue of humility is greatness, for the exercise of the soul therein, God is wont to make it mount by this ladder so that it may descend, and to make it descend so that it may mount, that the words of the Wise Man may thus be fulfilled, namely: Before the soul is exalted, it is humbled; and before it is humbled, it is exalted.’ 
3. Speaking now in a natural way, the soul that desires to consider it will be able to see how on this road (we leave apart the spiritual aspect, of which the soul is not conscious) it has to suffer many ups and downs, and how the prosperity which it enjoys is followed immediately by certain storms and trials; so much so, that it appears to have been given that period of calm in order that it might be forewarned and strengthened against the poverty which has followed; just as after misery and torment there come abundance and calm. It seems to the soul as if, before celebrating that festival, it has first been made to keep that vigil. This is the ordinary course and proceeding of the state of contemplation until the soul arrives at the state of quietness; it never remains in the same state for long together, but is ascending and descending continually.
4. The reason for this is that, as the state of perfection, which consists in the perfect love of God and contempt for self, cannot exist unless it have these two parts, which are the knowledge of God and of oneself, the soul has of necessity to be practised first in the one and then in the other, now being given to taste of the one–that is, exaltation–and now being made to experience the other–that is, humiliation–until it has acquired perfect habits; and then this ascending and descending will cease, since the soul will have attained to God and become united with Him, which comes to pass at the summit of this ladder, for the ladder rests and leans upon Him. For this ladder of contemplation, which, as we have said, comes down from God, is prefigured by that ladder which Jacob saw as he slept, whereon angels were ascending and descending, from God to man, and from man to God, Who Himself was leaning upon the end of the ladder.  All this, says Divine Scripture, took place by night, when Jacob slept, in order to express how secret is this road and ascent to God, and how different from that of man’s knowledge. This is very evident, since ordinarily that which is of the greatest profit in it–namely, to be ever losing oneself and becoming as nothing  –is considered the worst thing possible; and that which is of least worth, which is for a soul to find consolation and sweetness (wherein it ordinarily loses rather than gains), is considered best.
5. But, speaking now somewhat more substantially and properly of this ladder of secret contemplation, we shall observe that the principal characteristic of contemplation, on account of which it is here called a ladder, is that it is the science of love. This, as we have said, is an infused and loving knowledge of God, which enlightens the soul and at the same time enkindles it with love, until it is raised up step by step, even unto God its Creator. For it is love alone that unites and joins the soul with God. To the end that this may be seen more clearly, we shall here indicate the steps of this Divine ladder one by one, pointing out briefly the marks and effects of each, so that the soul may conjecture hereby on which of them it is standing. We shall therefore distinguish them by their effects, as do Saint Bernard and Saint Thomas,  for to know them in themselves is not possible after a natural manner, inasmuch as this ladder of love is, as we have said, so secret that God alone is He that measures and weighs it.
-  [Lit., rises to scale, know and possess.’]
-  Psalm lxxxiii, 6 [A.V., lxxxiv, 7].
-  St. Luke xiv, 11.
-  Proverbs xviii, 12.
-  Genesis xxviii, 12.
-  [Lit., and annihilating oneself.’]
-  Ut dicit Bernardus, Magna res est amor, sed sunt in eo gradus. Loquendo ergo aliquantulum magis moraliter quam realiter, decem amoris gradus distinguere possumus (D. Thom., De dilectione Dei et proximi, cap. xxvii. Cf. Opusc. LXI of the edition of Venice, 1595).