There is a thread running throughout God's Word concerning communion. Part of that communion has to do with suffering. I don't mean going through hard times in general; I'm referring to communion with Jesus in being rejected by the world. This is a part of the relationship of the bride of Christ. There is, I believe, a gentle wooing or loving invitation to fellowship in Christ's sufferings. It sounds strange, but for many the power of this relationship is not that it is a command to suffer but a relationship with Jesus in suffering. It is our willingness to respond to this invitation that can bring about an amazingly powerful result.
Let's look at some scriptures where Paul is speaking.
Galatians 6:17 (NIV)
Finally, let no one cause me trouble, for I bear on my body the marks of Jesus.
Ephesians 3:13 (NIV)
I ask you, therefore, not to be discouraged because of my sufferings for you, which are your glory.
Philippians 1:12-13 (NIV)
Now I want you to know, brothers, that what has happened to me has really served to advance the gospel.  As a result, it has become clear throughout the whole palace guard and to everyone else that I am in chains for Christ.
Philippians 1:20-21 (NIV)
I eagerly expect and hope that I will in no way be ashamed, but will have sufficient courage so that now as always Christ will be exalted in my body, whether by life or by death.  For to me, to live is Christ and to die is gain.
The Apostle Paul experienced a great deal of suffering for the cause of Christ. He knew this from his calling to serve Jesus, from his conversion. But the suffering wasn't just for Paul.
Philippians 1:27-30 (NIV)
Whatever happens, conduct yourselves in a manner worthy of the gospel of Christ. Then, whether I come and see you or only hear about you in my absence, I will know that you stand firm in one spirit, contending as one man for the faith of the gospel  without being frightened in any way by those who oppose you. This is a sign to them that they will be destroyed, but that you will be saved---and that by God.  For it has been granted to you on behalf of Christ not only to believe on him, but also to suffer for him,  since you are going through the same struggle you saw I had, and now hear that I still have.
1 Thessalonians 2:14 (NIV)
For you, brothers, became imitators of God's churches in Judea, which are in Christ Jesus: You suffered from your own countrymen the same things those churches suffered from the Jews,
1 Thessalonians 3:3-4 (NIV)
so that no one would be unsettled by these trials. You know quite well that we were destined for them.  In fact, when we were with you, we kept telling you that we would be persecuted. And it turned out that way, as you well know.
It has been granted to us not only to believe but also to suffer for him. Here we start to see that many of the churches suffered in the same manner as Paul did.
Colossians 1:24 (NIV)
Now I rejoice in what was suffered for you, and I fill up in my flesh what is still lacking in regard to Christ's afflictions, for the sake of his body, which is the church.
This is a fascinating verse. It almost appears as if Paul is saying that Jesus didn't really finish the suffering he needed to do and that Paul had to finish it up. But if you take this in context with what the church as been granted to suffer for Jesus then you start to see that Paul is saying this as an example. It is not just Paul that is filling up in his flesh what is still lacking, or still needs to be completed. It is an expression of our communion with Jesus.
Philippians 3:7-11 (NIV)
But whatever was to my profit I now consider loss for the sake of Christ.  What is more, I consider everything a loss compared to the surpassing greatness of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them rubbish, that I may gain Christ  and be found in him, not having a righteousness of my own that comes from the law, but that which is through faith in Christ---the righteousness that comes from God and is by faith.  I want to know Christ and the power of his resurrection and the fellowship of sharing in his sufferings, becoming like him in his death,  and so, somehow, to attain to the resurrection from the dead.
Paul was an example. His example of suffering and his words on the fellowship of sharing in Christ's sufferings are an invitation from the Lord to walk with the same heart and same fellowship. It is not a command. It is a call to communion.
2 Thessalonians 1:4-5 (NIV)
Therefore, among God's churches we boast about your perseverance and faith in all the persecutions and trials you are enduring.  All this is evidence that God's judgment is right, and as a result you will be counted worthy of the kingdom of God, for which you are suffering.
Matthew 24:9 (NIV)
"Then you will be handed over to be persecuted and put to death, and you will be hated by all nations because of me.
Mark 13:9-11 (NIV)
"You must be on your guard. You will be handed over to the local councils and flogged in the synagogues. On account of me you will stand before governors and kings as witnesses to them.  And the gospel must first be preached to all nations.  Whenever you are arrested and brought to trial, do not worry beforehand about what to say. Just say whatever is given you at the time, for it is not you speaking, but the Holy Spirit.
Luke 21:13 (NIV)
This will result in your being witnesses to them.
There are a lot of ministries that are working to bring the gospel of Christ to all nations and those works are amazing. We need those ministries. But the context of Jesus saying the gospel must be preached to all nations is within a context of persecution and suffering. It is this persecution that will result in the witness of Christ coming to the nations. Not just from being scattered but, again in this particular context, the persecution will place the gospel of Christ "on display." This is part of God's plan.
Don't think that I am saying we need to be focused on suffering. Our focus is on Jesus. I am all for avoiding suffering if possible. When talking about the last days and the persecution in the last days, Jesus said the following:
Luke 21:36 (NIV)
Be always on the watch, and pray that you may be able to escape all that is about to happen, and that you may be able to stand before the Son of Man."
I'm all for escaping any suffering I can. I think about this verse a lot. But at the same time I have a desire to have a deep communion with Jesus. When I take communion I don't just think about what Jesus did for me; I think about experiencing fellowship in what he did for me.
Many years ago some friends and I wrote a song. Here are the lyrics. This is the voice of the Bride to the one she loves.
Lamb of God; suffer in Your love
Feel my death, my life for me
Just for the unjust; suffering brings righteousness
To bring us back to God
I want to know You; Your joy, Your love, Your tears
Let me walk in Your steps and know Your ways
Let our minds be the same
I’m closer to You when I fellowship in Your pain
Let me love You. Let me die for You
Let me find true life in You
Oh, Jesus, make me just like you
Let me hide in You
Joy is what You bring; death to kill my sin
Freedom and liberty come within
As Your light pours forth like rain
I’m closer to You when I fellowship in Your pain
Sweet communion; let me die for the Son
Let me die for resurrection