My Muslim friend, The Historical Reliability of the Gospel, part One

The word Injil ("Gospel") is an Arabic translation of the Greek word Evangelion which means "happy message" or "good news," for it proclaims to all the absolute love of God towards sinners through the atoning death of Christ on their behalf; whoever truly believes in Him shall not perish but have eternal life (John 3:16).
Before addressing the belief that the Gospel of the Christians has been abrogated, we would say that anyone can accuse someone with whatever accusation he likes-but if there is no convincing evidence to back the accusation, it becomes null and void. Thus, those who say that the Gospel has been abrogated are obliged to mention:

• The original state of the verses abrogated
• The names of those who abrogated the Gospel, the time of abrogation and the purpose behind it.
• How the Gospel managed to be abrogated when, by the second century, thousands of Gospel texts had already spread to different countries in several languages.
• The method the abrogators used to cover up the alleged abrogation, which only the opponents of Christianity supposedly discovered and that hundreds of years after the alleged abrogation had taken place.

Since the opponents did not support their accusation with evidence, their accusation is baseless and ineffective. Nevertheless, we have examined the accusation from different perspectives, coming to the conclusion that the Gospel is free from any abrogation:

Neither the contemporaries of Christ nor their successors questioned the authenticity of any part of the Gospel text:

• Just ten days after the ascension of Christ into heaven, the Gospel began to spread orally among the people of Jerusalem who had lived with Him and knew everything about Him (Acts 2-7). Not even one of them disproved anything mentioned in the Gospel message. After that, in no more than three years, the Gospel spread to many Eastern and Western countries, being translated into the languages of these lands. Most of the inhabitants of these nations were permeated by Greek culture and influence then, so they did not accept the news until it had been thoroughly scrutinized from all angles (see Acts 17:10-12, 19:8-24). Historically, no one accused the evangelists of abrogating or distorting the Gospel.    
• Neither Jews nor pagans, despite their cynicism toward Christian beliefs and practices since the first century (owing to its spiritual essence, far loftier than mere human understanding), accused Christians of deleting from or adding to their Gospel.
• The heathen philosophers who accepted Christianity during the first centuries were famous for their research and debating. They themselves divided into factions over the explanation of particular verses in the Gospel. Each group was hostile toward the other and tried to find fault on various philosophical points. Yet, no group accused any of the others of abrogating the Gospel upon which all parties depended for research and discussion. Thus, their unfiled acceptance of the Gospel text proves they regarded it as authentic.

https://www.youtube.com/watch?v=G8AQnTO1c1Y