To Those Who Were Close By.
Most of the theology of the early Christian Church came from an interpretation of the crucificion and resurrection of Jesus Christ. The death of a loved one is difficult at anytime, but this particular significant death was very hard to understand.
Personally, I believe that Christ was trying to save everyone by this master plan that he had with God. It was awesome in its scope and power. In order to deal with all the livings souls that every existed, Jesus had to step out of time and correct what was wrong. This is dying "for the sins of all mankind."
The old universe ends and a new one begins in a blink of an eye. As John states in Revelation, "I saw a New Heaven and a New Earth." The Apostle Paul states in Corinthians, "As in Adam all die, so in Christ all will be made alive."
Everyone on Earth will encounter the crucificion memory of Jesus Christ in the vastness of time. At that time, the truth of this event will be revealed.