Final answer:
The Resurrection of Jesus is the key event first preached by women, as recorded in the New Testament Gospels.
Women were the primary witnesses to the empty tomb and the first to share the news of Jesus rising from the dead, indicating their influential role in early Christianity.
Step-by-step explanation:
The key aspect of the life of Jesus that was first preached by women was the Resurrection. According to the New Testament accounts in the Gospels, women were the initial witnesses to this event.
The Gospels of Matthew, Mark, Luke, and John describe how the women who followed Jesus came to the tomb bringing spices to anoint His body, only to find the tomb empty and be informed by an angel that Jesus has risen from the dead.
This foundation event of Christianity was first attested to by women, highlighting the significant role they played in the early Christian community.
In the history of early Christianity, women not only witnessed and shared news of the Resurrection but were also active participants and sometimes even leaders in the faith community.
The importance of the Resurrection itself cannot be overstated, as it forms the bedrock of the Christian belief in Jesus as the Christ, 'the anointed one', symbolizing hope and salvation for believers.