John Calvin on John 18:9

9. I have lost none. This passage appears to be inappropriately quoted, as it relates to their souls rather than to their bodies; for Christ did not keep the apostles safe to the last, but this he accomplished, that, amidst incessant dangers, and even in the midst of death, still their eternal salvation was secured. I reply, the Evangelist does not speak merely of their bodily life, but rather means that Christ, sparing them for a time, made provision for their eternal salvation. Let us consider how great their weakness was; what do we think they would have done, if they had been brought to the test? While, therefore, Christ did not choose that they should be tried beyond the strength which he had given to them, he rescued them from eternal destruction. And hence we may draw a general doctrine, that, though he try our faith by many temptations, still he will never allow us to come into extreme danger without supplying us also with strength to overcome. And, indeed, we see how he continually bears with our weakness, when he puts himself forward to repel so many attacks of Satan and wicked men, because he sees that we are not yet able or prepared for them. In short, he never brings his people into the field of battle till they have been fully trained, so that even in perishing they do not perish, because there is gain provided for them both in death and in life.

John 18:10-14

10. Then Simon Peter, having a sword, drew it, and struck the high priest's servant, and cut off his right ear; and the servant's name was Malchus. 11. Jesus therefore said to Peter, Put up thy sword into the sheath. Shall I not drink the cup which my Father hath given me? 12. Then the band, and the captain, and officers of the Jews, took Jesus, and bound him; 13. And led him away to Annas first; for he was father-in-law to Caiaphas, who was the high priest of that year. 14. And Caiaphas was he who had given counsel to the Jews, that it was expedient that one man should die for the people.