St. John Chrysostom, Patriarch of Constantinople, Doctor of the Church:
I do not speak rashly, but as I feel and think., I do not think that many priests are saved but that those that perish are far more numerous. The reason is that the office requires a great soul. For there are many things to make a priest swerve from rectitude, and he requires great vigilance on every side. Do you not perceive how many qualities a bishop must have that he may be apt to teach; patient towards the wicked, firm and faithful in teaching the Word? How many difficulties herein.
Moreover the loss of others is imputed to him. I need say no more. If but one dies without baptism, does it not entirely endanger his salvation? For the loss of one soul is so great an evil as no man can understand. If the salvation of one soul is of such importance that, for its sake, the Son of God became man and suffered so much, think of the penalty the loss of one soul will entail. (Third Homily, Acts of the Apostles)
They who are enlightened to walk in the way of perfection, and through lukewarmness wish to tread the ordinary paths, shall be abandoned. (Bl. Angela of Foligno)
They who are to be saved as Saints, and wish to be saved as imperfect souls, shall not be saved. (Pope St. Gregory the Great)
St. Teresa.... had she not risen from the state of lukewarmness in which she lived, she would in the end have lost the grace of God and been damned. ( St. Alphonsus Liguori)