The answer
God is omnipresent but His kingdom is in heaven and this is where our home will be. The Holy Bible teaches us "For our citizenship is in heaven, from which we also eagerly wait for the Savior, the Lord Jesus Christ" (Phil 3:20,21)."Jesus answered, "My kingdom is not of this world. If My kingdom were of this world, My servants would fight, so that I should not be delivered to the Jews; but now My kingdom is not from here" (Jn 18:36).
There is nothing wrong for people from different religion to shake hands, Christianity teaches us to love one another and more so to love our enemies. Our Lord Jesus Christ during His life on earth sat with the sinners. Being blamed for it His response was "Those who are well have no need of a physician, but those who are sick"(Mt 9:12). For a Christian to get close to other is a commandment of the Holy Bible "Let your light so shine before men, that they may see your good works and glorify your Father in heaven" (Mt 5:16).
The common everyday people who you think are not able to understand what we are saying have nature and the whole creation as a great witness for the attributes of God and they are without excuse.
"For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because what may be known of God is manifest in them, for God has shown it to them. For since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead, so that they are without excuse, because, although they knew God, they did not glorify Him as God, nor were thankful, but became futile in their thoughts, and their foolish hearts were darkened. Professing to be wise, they became fools, and changed the glory of the incorruptible God into an image made like corruptible man—and birds and four-footed animals and creeping things" (Rom 1:18-23).
Do not be deceived by the prince of this world, the devil, who wants us all to go astray and not to follow the path that leads us to salvation.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)