What the Apostles Taught

Keystone habits impact other habits of our lives.  For example, the habit of working out regularly can lead to improvements in dietary choices, sleeping more restfully, and overall better health.  The earliest Christians had a keystone commitment to the teachings of the apostles.  This commitment was combined with other key commitments listed in the book of Acts 2:42-47.
The apostles were Jesus' authorized representatives and messengers.  A list of the first 12 apostles is listed in Mark 3:13-19.  They spent about 3 years walking, talking, listening, seeing, and experiencing life with Jesus.  After Christ's resurrection, what we celebrate on Easter Sunday, he spent 40 days appearing to his followers at various times and places.  Jesus then gave his disciples their final instructions, "Go everywhere and announce the message of God's good news to everyone...Go out and train everyone you meet, far and near, in this way of life, marking them by baptism...Then instruct them in the practice of all I have commanded you..." (Mark 16:15 & Matthew 28:18-20 MSG)  After sharing these final words, Jesus left the earth, ascending into heaven.  At that point, it was up to the apostles and ALL the followers of Jesus to continue his work here on earth.
Peter, James, John, and the other apostles spent years sharing the Good News of what happened, what they experienced, and what Jesus taught and did during his time on earth.  Here is a small portion of what they taught and shared:
The apostle Peter said, "So let everyone in Israel know for certain that God has made this Jesus...to be both Lord and Messiah!" - Acts 2:36 NLT
The apostle Paul said, "We are here to proclaim that through this man Jesus there is forgiveness for your sins.  Everyone who believes in him is declared right with God..." - Acts 13:38-39 NLT
The apostle John wrote the entire account of Jesus' life, ministry, trial, crucifixion, and resurrection for this reason, "The disciples saw Jesus do many other miraculous signs in addition to the ones recorded in this book.  But these are written so that you may continue to believe that Jesus is the Messiah, the Son of God, and that by believing in him you will have {eternal} life by the power of his name." - John 20:30-31 NLT
To have a clearer understanding of who Jesus is and what the apostle taught, I encourage you to read "The Gospel According to Mark."  It is the shortest of the 4 written accounts of Jesus' life, death, and resurrection.  Scholars believe that Mark was an associate of the apostle Peter, so he combined messages, stories, and teaching he heard Peter share into a concise volume we know of as "Mark" or "The Gospel According to Mark."  You can read if for FREE by downloading YouVersion Bible App onto your smartphone or visit BibleGateway.com to read ALL 16 chapters online.
Keep in mind that the apostles didn't read about Jesus in a book or hear his words from a preacher, but they shared what they personally saw, heard, and experienced.  In spite of persecution and being threatened with death, the earliest Christians were Committed to Jesus Christ, what the apostles taught (Jesus' words and story), and life together (Acts 2:42).  What about you?