Fatima, Lourdes, Akita, Medjugoria, and so many other apparitions and inner locutions to Father Gobi in Mary Speaks to Her Beloved Priests, and so many other places. I am sure it is also to be found in the New Testament. St. John the Baptist cried out “Repent, for the Kingdom of Heaven is at hand.” That may not be an EXACT quote, but I don’t have a Bible right in front of me. That was, however, the message of St. John the Baptist. If it was important then, it still is today. Also, the popes have said it.
If you are not asking in order to debate, you may look up those messages. If you are seeking a debate about the subject…then what problem do you have with repentance?