Jesus said shortly after He was crucified to go make disciples of the Gentile nations. My question is “Why did Christianity grow so fast throughout the western cultures and nations and not eastern European and Asian nations?”
That is a good question! Of course, you are speaking about evangelism that took place in the First Century and I immediately thought of the Apostle Paul who was the “Apostle to the Gentiles” (see Acts 9:15; Romans 11:13; and Galatians 2:2, 7-8). We know that he took three long “missionary journeys” after he was saved (many Bibles have maps of those trips in the back of the Bible) and they were confined to nations in the Roman Empire. This much we know, that wherever Paul went, he was “led of the Holy Spirit” and thus we know that he was “not led of the Spirit to go to eastern Europe or Far East nations like China. We know from Acts 13:1-4 that Paul PRAYED for the leading and guiding of the Spirit and the Spirit answered those prayers. “Now in the church that was at Antioch there were certain prophets and teachers….as they ministered to the Lord and fasted, the Holy Spirit said, ‘Now separate to Me Barnabas and Saul for the work to which I have called them.’ Then, having fasted and prayed, and laid hands on them, they sent them away. So, BEING SENT OUT BY THE HOLY SPIRIT, they went down to Seleucia, and from there they sailed to Cyprus.” At times the Holy Spirit prevented them from going to certain places, “Now when they had gone through Phrygia and the region of Galatia, THEY WERE FORBIDDEN BY THE HOLY SPIRIT TO PREACH THE WORD IN ASIA” (Acts 16:6). You can read on in verses 9-10 to see God leading Paul to Macedonia instead (where he preached the gospel in the city of Philippi). God knew where He wanted Paul to go, and Paul was obedient to the Holy Spirit’s leading. God is sovereign and he led Paul, the Apostle to the Gentiles, to specific nations in the Roman Empire, to accomplish His purposes in those early days of Christianity.
It should be noted that our God is a very “practical God” and with Paul being “one man” there were two practical reasons for limiting his outreach, 1) TIME, and 2) LANGUAGE. There were not enough hours in the day and days in the year for Paul to do any significant work, including learning new languages and new cultures and engaging in long-distance travel, in countries outside of the Greek-speaking world that made up the Roman Empire. These prevented Paul from reaching faraway countries like India and China in the East, and much of Africa in the South. Yet there is some historical evidence that the Apostle Thomas traveled to India with the gospel after having learned their language. And it is possible other apostles traveled to other countries to evangelize.
We do know from Scripture that people from other countries had come to Jerusalem to celebrate the Feast of Pentecost and many of them heard the gospel and were saved. In Acts 2:5 we read, “And there were dwelling in Jerusalem Jews, devout men, FROM EVERY NATION UNDER HEAVEN.” As we read on in verses 6-12, we see that people from at least 15 countries heard the “wonderful works of God” spoken in their own language and we know from verses 41 & 42 that 3,000 souls “received his word” and were “added to the company of believers” that day. Many of them no doubt returned home and thus we can surely assume that they preached the gospel to their loved ones and acquaintances in their native homeland. And then we have the amazing conversion account of the Ethiopian Eunuch in Acts 8:26-39 who heard the gospel from Philip the evangelist who “preached Jesus to him” from Isaiah chapter 53 (verses 26-35). The eunuch believed and “he went on his way rejoicing” (verses 36-39). Surely the joy of salvation that filled his heart that day led him to preach Jesus to his fellow-countrymen in Ethiopia upon his return home. Perhaps this is why Christianity is the largest religion in Ethiopia today. We can conclude from these examples that God has His way of spreading the gospel even though He has not recorded the results of those evangelistic efforts in His Word. As time went on in later centuries, Missions were formed in many countries in Eastern nations, and even though religions like Buddhism and Hinduism were prominent there, the gospel of Christ has gone forth and souls are being saved. (DO) (516.5)