6 When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?
The Apostles, even after three years of walking with the Lord, witnessing His death, experiencing His resurrection, have an agenda that does not conform to Christ's agenda. They have received this great commission on a number of occasions & yet have still not understood that the Son of Man came for all of mankind & that all of mankind had to receive the Word.
Christians in the modern world must still heed the Lord's answer in v.7. Whether it be eschatology, ministry, mission or even personal prognostications or agendas, the future is not for us to know or to act upon but the present is ours in which to be. God will bring the kingdom in when He will. We are not to wait around for Him to do so, but to "be witnesses unto [Christ] both in Jerusalem, & in all Judea, & in Samaria, & unto the uttermost part of the earth," (v.8) ie everywhere & everyone. We are promised the Holy Spirit's lead in these endeavours (v. 8) & we carry the promise that Christ has all authority in heaven & on earth, ruling all nations, the only "superpower" there is & that all that power will go before us & He will be with us always, even unto the end of the world (Mt.28:20)
Even so, many do not like this answer, but, as often happens, God always answers just not always with the answer we would like. It brings to mind the many agendas we still sometimes have & try to impose upon God. Many are delighted to go God's way as long as He is going their way. We must learn to conform our lives & our desires to God's agenda. Only then will we know the fullness of worship ie surrendering to God all that we have & all that we are. We can not fully worship God while retaining the individual, national, or global agendas we desire that are outside God's agenda. Ministry, financial, political -- all agendas must be subservient to His else we are not walking in His way but ours. We may find certain tasks annoying, certain places too distant, certain people unappealing. These are to be of no account. Whatever, wherever & to whomever God leads us is our duty for service. History is replete with examples of reluctant prophets & missionaries from Jonah to Thomas (see "Thomas in India" below) to St. Patrick (whom most mistake for being Irish; he wasn't; he was a British boy captured by Irish warriors & taken into slavery in Ireland who, after escaping some 13 years later, returned to bring the Gospel to the land of his former captivity). How much more so should our 21st century comfort laden world be? We must be willing to go God's way, even if it's not our way. Obedience must accompany faith, else one must question where that faith is actually placed.
What is most surprising, when you can truly reach a point of surrender to God, we often find that what He has in mind is so much greater & far reaching than anything we might imagine. Here the Apostles are focused on just Israel. Christ tries to make clear to them over & over in the Great Commission (see here & Mt 28) that His vision encompasses the entire world, everywhere the Apostles knew of & beyond to lands that wouldn't be discovered for another 1400 years! Christianity would spread across the globe from this small collection of disciples huddled in an upper room. That, then, is the essence of this passage. Give up your own small visions for yourself & embrace the greater vision of God. The rewards of doing so may not come to us in this lifetime. Eleven of the twelve died horrible deaths in martyrdom while the only one to die of old age (ironically, the youngest, John) spent most of his years living in prison or in exile. However, this is the essence of faith -- knowledge of that which is unseen (Heb 11:1); knowledge that heaven carries a reward greater than anything to be found in this life. Such is part of embracing God's greater vision for us & mankind.