"the divine uncreated energies of God
Clarify, please."
The quick answer is "grace". All we can perceive of God are the results of His divine energies and generally, except for those in a very advanced state of theosis, or maybe even complete theosis, we can't perceive those uncreated energies themselves. But everything good in creation, indeed creation itself, is a manifestation of those divine energies. The essence of God is ineffable, unapproachable and not perceivable for man. One of the Fathers likened them to the rays of the sun which a blind man cannot see but senses because of the heat they generate. Orthodoxy believes that these energies are an attribute of or a sort of "emination" from God and as such are of necessity uncreated. Roman Catholicism, generally holds, or at least did, that these energies, grace if you will, are creations of God. This has certain implications for an understanding of the sacraments. At any rate, it is with these uncreated divine energies that we come into perfect union with when we reach a state of theosis. This theology is generally best presented by the writings of certain of the Cappadocian Fathers, +Symeon the New Theologian and, of course, +Gregory Palamas. Here's what Palamas wrote:
"Three realities pertain to God: essence, energy, and the triad of divine hypostases. As we have seen, those privileged to be united to God so as to become one spirit with Him - as St. Paul said, 'He who cleaves to the Lord is one spirit with Him' (I Cor. 6:17) - are not united to God with respect to His essence, since all theologians testify that with respect to His essence God suffers no participation.
Moreover, the hypostatic union is fulfilled only in the case of the Logos, the God-man.
Thus those privileged to attain union with God are united to Him with respect to His energy; and the 'spirit', according to which they who cleave to God are one with Him, is called the uncreated energy of the Holy Spirit, but not the essence of God"
"The grace of deification thus transcends nature, virtue and knowledge, and `all these things are inferior to it.' Every virtue and imitation of God on our part indeed prepares those who practice them for divine union, but the mysterious union itself is effected by grace. It is through grace that `the entire Divinity comes to dwell in fullness in those deemed worth,' and all the saints in their entire being dwell in God, receiving God in His wholeness, and gaining no other reward for their ascent to Him than "God Himself." St. Gregory Palamas
And others:
"The Son of God has become Son of Man in order to make us...sons of God, raising our race by grace to what He is Himself by nature, granting us birth from above through the grace of the Holy Spirit and leading us straightway to the kingdom of heaven, or rather, granting us this kingdom within us, in order that we should not merely be fed by the hope of entering it, but entering into full possession thereof should cry: our 'life is hid with Christ in God.'." St. Simeon the New Theologian
"It is my opinion that our intellect does not have a natural power to be moved to the divine vision of Divinity. And in this one deficiency we are the peers of all the celestial natures, for both in us and in them grace moves that which is alien by nature both to the human intellect and to the angelic. For divine vision concerning the Godhead is not to be numbered among the other kinds of divine vision. For we possess divine vision of the natures of things through participation in their twofold nature, because there is a portion of all things in us. But we do not have a portion of the nature of the Divine Essence, and so neither do we have by nature divine vision of it." +Isaac the Syrian
These energies are sometimes manifested as a sort of Light without any apparent source. The Light on Mt. Tabor is an example of this, but The Church has many stories of saints being surrounded by this Light (+Symeon the New Theologian for example, or +Mary of Egypt). The vision of the uncreated Light is a result of a life which has been spent holding tight to God, so tight that that person is taking on a great similitude to Christ, in other words, arriving at that "likeness" of God which we lost in The Fall.
"Thus the deifying gift of the Spirit is a mysterious light, and transforms into light those who receive its richness; He does not only fill them with eternal light, but grants them a knowledge and a life appropriate to God. Thus, as St. Maximus teaches, St. Paul lived no longer a created life, but "the eternal life of Him Who indwelt him." Similarly, the prophets contemplated the future as if it were the present." St. Gregory Palamas
"Can a man take fire into his bosom, and his clothes not be burned?' (Prov. 6:27) says the wise Solomon. And I say: can he, who has in his heart the Divine fire of the Holy Spirit burning naked, not be set on fire, not shine and glitter and not take on the radiance of the Deity in the degree of his purification and penetration by fire? For penetration by fire follows upon purification of the heart, and again purification of the heart follows upon penetration by fire, that is, inasmuch as the heart is purified, so it receives Divine grace, and again inasmuch as it receives grace, so it is purified. When this is completed (that is, purification of heart and acquisition of grace have attained their fullness and perfection), through grace a man becomes wholly a god." St. Simeon the New Theologian
"He as God of all gave strength to me, weak as a mortal, as He said: 'Hold out your hand and I shall give you strength.' For how would I have had the power unless the very thing happened which He said would take place? How would I have had the ability to baptize the abyss, Since I am mortal, Had I not first received and claimed power from on high? For I realize now that He is standing by me That I am greater than I was formerly. I am something different, I am changed, glorified, As I behold and baptize The unapproachable Light." St Romanos the Melodist