The Bishop of Carlisle made "significant errors of judgement" in giving a character reference for a colleague who molested children, the Church of England has found.
The Right Reverend James Newcome submitted the reference to the judge who jailed the Reverend Robert Bailey.
He has been given an "informal rebuke" by the Archbishop of York which will remain on file, the Church said.
Bishop Newcome repeated his apology to those "hurt by the submission".
"I understand the anguish this will have caused those who suffered as a result of his crimes," he said.
"This was something I did at his request and which I later recognised to have been an error of judgement on my part, leading to my request that it be withdrawn."
The Church's National Safeguarding Team began an investigation into the bishop's conduct following criticism of his decision to submit the character reference.
It said: "The Church takes all safeguarding issues very seriously and is continuing to learn lessons from the Independent Inquiry into Child Sexual Abuse which criticised the Church's response to survivors both at its public hearings and in its final report last October."
Bailey admitted child sex offences committed while he was working in Bishops Canning, near Devizes.
He had been a vicar in the Diocese of Carlisle from 1999 until his retirement to Salisbury in 2011 and had known Bishop Newcome for 18 years.
The bishop said he understood "the need to learn from this situation and so I welcome the opportunity to engage wholeheartedly in further safeguarding training opportunities".
He added: "Until that training is completed, I shall continue to step back from all diocesan safeguarding matters."