"For it seems to me that God has put us apostles on display at the end of the procession, like men condemned to die in the arena. We have been made a spectacle to the whole universe, to angels as well as to men." NIV translation
This verse refers to the shows that the Romans had put on at the coliseum where Christians were killed for sport. Likewise, most of the apostles were killed in public spectacles that were put on in an attempt to keep people from accepting Jesus Christ. This is the same type of thing that will happen to those that refuse to worship the beast as we see in Revelation 13. We also see that Paul made a distinction between himself (as an apostle) and the other believers. There are many, today, that are giving themselves the title of apostle but they forget that Jesus made a distinction and personally chose these men.
"We are fools for Christ, but you are so wise in Christ! We are weak, but you are strong! You are honored, we are dishonored!" NIV translation
Paul continues to show us the difference between himself and the other leaders. We see that the apostles were not raised up while they walked this earth but they will be rewarded in heaven. They will each have a throne in heaven as we see in Revelation 4. Many who are claiming this "title" for themselves are not walking in the same way as they have fancy cars, fancy homes, etc. and are not being persecuted for Christ.
"To this very hour we go hungry and thirsty, we are in rags, we are brutally treated, we are homeless. We work hard with our own hands. When we are cursed, we bless; when we are persecuted, we endure it; when we are slandered, we answer kindly. Up to this moment we have become the scum of the earth, the refuse of the world." NIV translation
Paul continues to describe what the apostles went through and we see that they did not have a bunch of earthly possessions. They worked with their hands and were not lifted up like royalty. Instead, they were treated in much the same way that Jesus was as He walked this earth.
"I am not writing this to shame you, but to warn you, as my dear children. Even though you have ten thousand guardians in Christ, you do not have many fathers, for in Christ Jesus I became your father through the gospel." NIV translation
Paul had brought these people to faith in Jesus Christ and a new birth. Because of that new birth and his part in bringing them to that point, he was considered to be their new father. He reminds the believers that there may be thousands of Christians who help to grow and protect you in your faith but they did not have a part in your new birth as Christians. With that relationship, comes responsibility and that is why Paul is warning them about false apostles and others.