Grace, by a secret instinct sets us at peace concerning our salvation and the intimate reconciliation in God of infinite justice, mercy, and sovereign liturgy. Grace, by this secret instinct, sets us thus at peace, because it is itself a real and formal participation in the divine nature, in God's intimate life in the very Deity, in which all the divine perfections are absolutely identified.
If we stress too much our analogical concepts of the divine attributes, we set up an obstacle to the contemplation of the revealed mysteries. The fact that these concepts are distinct from one another, like small squares of mosaic reproducing a human likeness, is why they harden the spiritual aspect of God for us. Wisdom, absolute liberty, mercy, and justice seem in some way to be distinct in God, and then His sovereignly free good pleasure appears in an arbitrary light, and not entirely penetrated by wisdom; mercy seems to restricted, and justice too rigid. But by faith illumined by the gifts of understanding and wisdom, we go beyond the literal meaning of the Gospel and imbibe the very spirit of God's Word. We instinctively feel, without seeing it, how all the divine perfections are identified in the Deity, that is superior to being, the one, the true, the intellect, and love. The Deity is superior to all perfections that are naturally susceptible of participation, these being contained in it formally and eminently without any admixture of imperfection. The Deity is not naturally susceptible of participation, either by angel or man. It is only by grace, which is essentially supernatural, that we are permitted to participate in the Deity, in God's intimate life, in as much as the latter is strictly divine. Thus it is that grace is instrumental in causing us mysteriously to reach, in the obscurity of faith, the summit where the divine attributes are identified. The spiritual aspect of God for us is no longer hardened. We do not see His countenance, but we instinctively feel it, and this secret instinctive feeling, in the supernatural abandonment of ourselves, gives us peace.
Reginald Garrigou-Lagrange O.P. in “Predestination”