Suffering is suffering no matter what form it takes. We often don't think that we are suffering because we are not be persecuted but that is a false assumption. There is no difference between suffering in persecution or suffering in sickness. John Piper elaborates here:
The most significant difference between sickness and persecution is that persecution is an intentional hostility from someone because we are known to be Christians, but sickness is not. Therefore, in some situations, to choose to be public Christians is to choose a way of life that accepts suffering, if God wills (1 Peter 4:19). But suffering may result from living as a Christian even when there is no intentional hostility from unbelievers. ...[A]ll suffering that comes in the path of obedience is suffering with Christ and for Christ—whether it is cancer or conflict. And it is “chosen”—that is, we willingly take the path of obedience where the suffering befalls us, and we do not murmur against God. ...All experiences of suffering in the path of Christian obedience, whether from persecution or sickness or accident, have this in common: They all threaten our faith in the goodness of God and tempt us to leave the path of obedience. Therefore, every triumph of faith and all perseverance in obedience are testimonies to the goodness of God and the preciousness of Christ—whether the enemy is sickness, Satan, sin, or sabotage. Therefore, all suffering, of every kind, that we endure in the path of our Christian calling is a suffering “with Christ” and “for Christ.” With Him in the sense that the suffering comes to us as we are walking with Him by faith and in the sense that it is endured in the strength He supplies through His sympathizing high-priestly ministry (Hebrews 4:15). (From Desiring God by John Piper, pages 256-257.)
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