
In general, the Process of our Salvation can be viewed in three stages in the Process of God being All in all:
(1) In the Most Holy Trinity ad intra before reaching out ad extra in Its boundless love to create and unite with all, God the Most Holy Trinity is infinitely and eternally present All in All of the Most Holy Trinity ad intra. One may call this uncreated omnipresence of God the Uncreated Universe of God. Just as the created universe is composed of created energies, God's Uncreated Universe is made of God's Uncreated Divine Energies. As such, before the existence of the present created universe (of universes), there was the Uncreated Universe of God.
(2) In a process, the present created universe and everything within it have been created by God to be united with God in love. Not only has the created universe (or energies) been created by God's Uncreated Universe (or Energies), but the former is also permeated and embraced through and through by the latter. Unfortunately, by refusing to be open to the Mystery of the Most Holy Trinity in God's Divine Revelation, modern science and cosmology, etc., have unwisely deprived themselves of this uncreated reality. Advanced scientific technology keeps sending missions to outer space only to obtain half-truths for us concerning what is really out there.
Prior to original sin, God was All in all of creation. In fact, God said "very good" six times to creation in Genesis 1. However, because of sins (original, historical, social, personal, etc.), there has been an immense darkness or veil made of sinful energies, invisibly so, permeating all in the present universe (with the exception of God and those in Heaven). In other words, God is no longer All in all in us. God may still be present in all but, due to our sins and their consequences, we cannot fully see God's omnipresence. Neither can we know it, appreciate it, feel it, touch it, and embrace it intimately.
In order that we "may be filled with all the fullness of God" once for all (Eph 3:19), this sinful veil together with all our sins which have brought us countless disharmonies, damages and sufferings must be thoroughly wiped out. As this task is completely beyond any human means and capability, God has to do it Himself. Indeed, the way God has done it is through the Mass, i.e., the infinite Holy Sacrifice of Christ Himself, the Saviour of all creation, visible and visible. It is Jesus who has shed all His Precious Blood in His Passon and Death for all.
As we know, there has only been one Mass in salvation history in which the Son of God Himself personally suffered, died and resurrected for all creation two thousand years ago. Responding to Christ's demand, the Church commemorates it daily, especially during the Triduum, i.e., from Holy Thursday to Easter Vigil on Holy Saturday. It is the First Mass, the Last Mass and the Only Mass. All the other Masses, although possessing the same exact infinite value, are simply historical re-enactments of God's Self-Sacrifice to save us from our sins and their untold consequences with which we are still struggling. These other Masses are the Church's heroic efforts to help God continue to reach out to heal and redeem our wounded world (except Hell and all those who have entered there through their free will).
(3) In Heaven, once again the Most Holy Triune God will be All in all of us (cf. 1Cor 15:28; etc.), while remaining All in All of the Most Holy Trinity ad intra for all eternity. It is the ultimate fulfillment of the Most Holy Trinity ad extra.
The whole created universe will then joyfully let God's Uncreated Omnipresence or Universe come alive in an everlasting union or reunion. Being part of the whole Family of Holy Angels and Saints, each of us will be intimately united with God in infinite love and holiness. We will all be filled with God's inexpressible happiness, peace, wisdom, beauty and countless other gifts forever and ever in the Heavenly Family Party which will never end.
In brief, God being All in All (in the Holy Trinity ad intra) is the blueprint of God being All in all (in the Holy Trinity ad extra) which can only be fulfilled by God's initiative at the First Mass and our subsequent cooperation with its infinite value in prayer and deeds*.

*As each celebration of the Mass is activating Christ's infinite merits gained through the First Mass, allowing us to be personally and intimately united with the Most Holy Trinity through the Holy Communion of Christ Himself, perhaps we should participate in each Holy Sacrifice of Christ as if it is the first one, the last one and the only one.
Most Holy Trinity, have mercy on us! Help us with our unbelief! We thank You with all our hearts for the First Mass as it is being tapped into daily for the salvation and transformation of all believers and unbelievers alike!
© John Cheng, Grace Institute of the Holy Eucharist/ Holy Thursday April 1, 1999
