Kosta is correct, but I see he is emphasizing one part of our "relationship" with God - perhaps it might seem he is disregarding the other part.
God gives His own life and friendship to us. We call this gift grace. We do not earn or deserve God's grace. Grace allows us to become God's adopted children and respond to His abundant love. I think this explains both "parts" of the relationship - that God takes the initiative, God provides us with Grace, God provides us the impetus to respond to Him - and YET, We also are called to RESPOND. Thus, because of the existence of free will (the ability to respond to God implies the ability to reject God), we DO, in some manner, are called into a relationship. We give of ourselves, even if it is miniscule compared to God. God is not looking for quantity, but the giving of our SELF. If we are to become like God, we must "act" like Him (which we cannot do without Him - John 15). We must love others, even our enemies. We must place God in our lives first, like Christ did. We must give of ourselves totally, just as Christ did. THAT is the relationship we are in. Through the Incarnation, man CAN be enabled to partake in His most holy divine nature. I feel confident that Kosta agrees that the Incarnation allows us to partake in the divine nature, although he will probably use different words, such as theosis and divinization. But the concept is the same. We are to become like Christ ONLY because He became like us (St. Athanasius said something to that effect - God became man so that we could become "gods" [not ontologically!])
Jesus came to proclaim the Kingdom. God has always desired to share of Himself with us. To do this, Jesus came to establish the Kingdom here, even now, but not yet! Jesus told us what the Kingdom of Heaven is like. Not only is it the Church on earth, but it is our relationship with Christ Himself. Through this Church, the people whom we fellowship with, the pastors who teach the Word to us, the priests who administer God's graces to us visibly through the sacraments, the Kingdom is made present even now. And ESPECIALLY through the Mass (Divine Liturgy), the Kingdom of Heaven comes and joins in with our own participation with Christ in His eternal offering of Himself to the Father.
God has covenanted with His people. HE took the initiative and HE binds Himself to this covenant. But was it ALWAYS one-way? The Mosaic Covenant DEMANDS obedience to God. Christ did not change that. We are STILL commanded to obey the Commandments. However, Christ specifically fulfilled the Law by EXPANDING it - "you have heard it said...but I tell you - if you even look at a woman with lust in your heart, you have committed adultery", and so forth. In Matthew 5-7, Jesus tells us what our relationship must be based upon - love of God and neighbor. We are not to be like the hypocrites who follow the Law, but not in their hearts. Thus, we MUST love - and by loving our neighbor, we love God. This is the relationship we are called to partake in. It is not one-sided - although it is ultimately dependent upon God's graces. Would you agree, Kosta?
The Great Schism occurred five hundred years before Reformation. The main difference was papal authority and the issue of Filioque as it was inserted in the Nicea Creed by the Spanish clergy in the 6th century.
I think our respective communities grew apart culturally first. We hardly spoke each other's language. Politically, we were separate after the fall of Rome in the early 400's to the barbarians. Leadership-wise, we took different paths, also. Rome had no or little political pressure for many years, while Constantinople lived under the often-heretical emperor. Thus, East and West took different paths ecclesiastically and culturally many years before the Schism or even the Filioque (which was not listed among the reasons in 1054).
The Filioque was taken as a slap in the face by the Greeks because it was done without a Council and because the Greeks perceived that it was heretical teaching. Simply put, it was a huge misunderstanding and a lack of tact on the part of Rome. Theologically, the formula is acceptable (though I think "through" rather than "and" would be better). The Papacy, I believe, was not a real problem for the East (although I think the Bishops in Constantinople would have desired for Rome to stop "butting in") - they appealed to him over and over again to fight heresy. I believe the split is more over lack of understanding each other culturally. Polemics naturally didn't endear us to each others positions! Theologically, there are very few issues that we disagree on. But because we have different points of view (the Trinity can be approached from more than one direction!!!), we often fail to understand that we agree, but said differently. We pray that God wills that His Church re-unite.
Brother in Christ
I was emphasizing God's overwhelming and lopsided relationship to counter the Protestant notion of some "fellowship" or "partnership," which trickles into the sola scriptura arrogance that tends to make every man his own pope and a "junior partner" in God's Firm. Christian God is humble. Protestants don't know what that means; they are directed to "sin boldly" by Luther.
Let's not fool ourselves that our response to God is of any real value to Him save for His love for us. And you point to a very important detail: that we must give ourselves totally to God and I will say that none of us does. The woman who gave her last two copper coins to God, gave little, but she gave everything to Him. That's what Christ taught us. He taught us that she loved God with all her heart, mind and soul.
Theologically, the [filioque] formula is acceptable (though I think "through" rather than "and" would be better)
Theologically, it is understandable inasmuch as it shows Latin error. +Gregory Palams describes the Holy Spirit as the eros (love) between the Father and the Son, as the Latin theologians do, but he makes sure to underscore that the Holy Spirit exists only from the Father, as does the Son. We could go on, of course, but the original Creed goes to the very eternal fountain of Divinity which is unmistakably and incorruptibly associated only with the Father, as the source of everything and all, including the Divinity.
Thanks very much for the whole explanation, that helps a lot!