49 Nor must we think that St. Leo was preaching a doctrine that had never before been taught. For, that his supreme office as universal pastor came from Christ Himself was also the teaching of his predecessors St. Innocent 143 and St. Boniface I, (44) and was in full accord with those passages of the Gospels which he so often expounded ( Matt . 16:17-18; Luke 22::31-32: John 21:15-17). He frequently referred to "the care which, principally by divine mandate, We must have for all the churches." (45)
Source: Aeterna Dei Sapientia (Vatican.va)