Was asked about a line in a written vow of offering: to suffer now and forever" if it be God's will. We discussed pain in other dimensions or perspectives as joy. I was asked for Scripture and documented example, not signs and wonders. Drew a blank although certain joy in suffering is in Scripture. Later, bits of Scripture popped into the present moment mind, too late for earlier discussion. Seems everything has a reason.
Perhaps Jesus preferred my slowing down the thoughts, search the Bible, write out the supportive Scriptures, share them, ponder them. So here they are, fresh from the New American Bible, The Catholic Study Bible, Second Edition. I will not comment. They each provide positive aspects of suffering and some suggest the mystical joy in suffering.
As for suffering now and forever, the key is: if God wills. The forever requires delving into mystical theology as well as private revelations in which Jesus has appeared to various saints as the suffering Christ, sometimes asking them to unite in His suffering, sometimes confiding he suffers for indifferent, neglectful, or unrepentant souls. In such visions, Jesus may ask the person to whom He appears if the person is willing to suffer with him for souls. The joy resulting from this very real suffering is mystical in nature, as the topic of reparative suffering is bejeweled mystery.
[For more on topic see Pope John Paul II's Salvifici Doloris (1984) and Pope Pius XI's Miserentissimus Redemptor (1928) and Calitate Christi Compulsi (1932). Of note, also, is Pope Pius XII's call for a crusade of world-wide reparation in 1942.]
Now for some Scriptures relative to joy in suffering.
Saint Paul:
Not only that, but we even boast of our afflictions, knowing that affliction produces endurance, and endurance proven character, and proven character, hope, and hope does not disappoint, because the love of God has been poured out into our hearts through the holy Spirit that has been given to us. Romans 5:3
The Spirit itself bears witness with our spirit that we are children of God, and if children, then heirs, heirs of God and joint heirs with Christ, if only we suffer with Him so that we may also be glorified with Him. Romans 8:17
Blessed be the God and Father of our Lord Jesus Christ, the Father of compassion and God of all encouragement, who encourages us in our every affliction, so that we may be able to encourage those who are in any affliction with the encouragement which we ourselves are encouraged by God. For as Christ's sufferings overflow to us, so through Christ does our encouragement also overflow. If we are afflicted, it is for your encouragement and salvation; if we are encouraged, it is for your encouragement, which enables you to endure the same sufferings that we suffer. II Corinthians 5:3-6
But whatever gains I had, these I have come to consider a loss because of Christ. More than that, I consider everything as a loss because of the supreme good of knowing Christ Jesus my Lord. For his sake I have accepted the loss of all things and I consider them so much rubbish, that I may gain Christ and be found in him, not having any righteousness of my own based on the law but that which comes through faith in Christ, the righteousness from God, depending on faith to know him and the power of his resurrection and the sharing of his sufferings by being conformed to his death, if somehow I may attain the resurrection from the dead. Philippians 3:7-11
For to you has been granted, for the sake of Christ, not only to believe in him but also to suffer for him. Philippians 1:29
Now I rejoice in my sufferings for your sake, and in my flesh I am filling up what is lacking in the afflictions of Christ on behalf of his body, which is the church.... Colossians 1:24
Attributed to St. Paul as author of Letter to the Hebrews:
For the sake of the joy set before him he endured the cross, despising its shame, and has taken his seat at the right of the throne of God. Hebrews 12:2
St. Peter:
Therefore, since Christ suffered in the flesh, arm yourselves also with the same attitude (for whoever suffers in the flesh has broken with sin), so as not to spend what remains of one's life in the flesh on human desires, but on the will of God. 1 Peter 4:1
But rejoice to the extent that you share in the sufferings of Christ, so that when his glory is revealed you may also rejoice exultantly. 1 Peter 4:13
St. James:
For the sake of the joy set before him he endured the cross, despising its shame, and has taken his seat at the right of the throne of God. Hebrews 12:2
Job in The Book of Job:
Even that God would decide to crush me, that he would put forth his hand and cut me off! Then I should still have consolation and could exult through unremitting pain, because I have not transgressed the commands of the Holy One. Job 6:10
And from Jesus in the Gospel of St. John, on which we may educe that in suffering we will share His joy as stated in Jesus' words of invitation and exhortation:
If you keep my commandments, you will remain in my love, just as I have kept my Father's commandments and remain in his love. I have told you this so that my joy may be in you and your joy may be complete. John 15:10-11