St. Paul the Apostle wrote, “And not only that, but we also glory in tribulations, knowing that tribulation produces perseverance; and perseverance, character; and character, hope. Now hope does not disappoint, because the love of God has been poured out in our hearts by the Holy Spirit who was given to us." (St. Paul's Letter to the Romans 5.3-5, NKJV)
St. John Chrysostom's commentary:
"And what he says is not 'you should glory,' but we glory, giving them encouragement in his own person. Next since what he had said had an appearance of being strange and paradoxical, if a person who is struggling in famine, and is in chains and torments, and insulted, and abused, ought to glory, he next goes on to confirm it. And (what is more), he says they are worthy of being gloried in, not only for the sake of those things to come, but for the things present in themselves. For tribulations are in their own selves a goodly thing.
How so? It is because they anoint us unto patient abiding. Wherefore after saying we glory in tribulations, he has added the reason, in these words, 'Knowing that tribulation worketh patience.' Notice again the argumentative spirit of Paul, how he gives their argument an opposite turn. For since it was tribulations above all that made them give up the hopes of things to come, and which cast them into despondency, he says that these are the very reasons for confidingness, and for not desponding about the things to come, for 'tribulation,' he says, 'worketh patience.'
St. John Chrysostom’s Homilies on the Epistle to the Romans, NPNF:
Icon of St. John Chrystostom - public domain.