"It was after Peter had been led to self-renunciation and entire reliance upon divine power, that he received his call to act as an undershepherd. Christ had said to Peter, before his denial of Him, “When thou art converted, strengthen thy brethren.” Luke 22:32 . These words were significant of the wide and effectual work which this apostle was to do in the future for those who should come to the faith. For this work, Peter's own experience of sin and suffering and repentance had prepared him. Not until he had learned his weakness, could he know the believer's need of dependence on Christ. Amid the storm of temptation he had come to understand that man can walk safely only as in utter self-distrust he relies upon the Saviour. AA 515.1"
"But I have prayed for thee, that thy faith fail not: and when thou art converted, strengthen thy brethren."
Ellen White directly references Luke 22:32 in this passage.
"At the last meeting of Christ with His disciples by the sea, Peter, tested by the thrice-repeated question, “Lovest thou Me?” ( John 21:15-17 ), had been restored to his place among the Twelve. His work had been appointed him; he was to feed the Lord's flock. Now, converted and accepted, he was not only to seek to save those without the fold, but was to be a shepherd of the sheep. AA 515.2"
"So when they had dined, Jesus saith to Simon Peter, Simon, son of Jonas, lovest thou me more than these? He saith unto him, Yea, Lord; thou knowest that I love thee. He saith unto him, Feed my lambs. He saith to him again the second time, Simon, son of Jonas, lovest thou me? He saith unto him, Yea, Lord; thou knowest that I love thee. He saith unto him, Feed my sheep. He saith unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said unto him, Lord, thou knowest all things; thou knowest that I love thee. Jesus saith unto him, Feed my sheep."
Ellen White directly references John 21:15-17 in this passage.