Lazarus was the brother of Mary and Martha (see Luke 18:38-42). He was ill and his sisters sent for Jesus to come and heal him. However Jesus arrived too late and Lazarus was dead, in fact he had been in the tomb for four days! Mary said it wouldn’t have happened if Jesus had been with them. Deeply moved, Jesus raised Lazarus from death (John 11).
This event caused quite a stir and Lazarus himself went around telling everyone about Jesus, so much so that the authorities plotted to do away with Lazarus to keep him quiet (John 12:9-11).