Paul’s epistle to the Romans is a powerful book whose primary theme is the righteousness from God. It covers key themes to the Christian faith such as, righteousness, sin, justification and sanctification. Romans is more of a theological treatise then a personal letter, and it contains the core of Paul’s theology and teaching. It was intended in part to introduce Paul to the Christians in Rome most of whom have likely never heard Paul teach.
Paul starts this letter with a typical Hellenistic pattern of a greeting. That is the names himself as the author. He then names the addressee of the letter, and closes the introduction with a greeting in verse 7. This creates the longest introduction section of any of Paul’s letters, which is fitting since it is the only letter sent to a church that would not know him.
Following this pattern the very first word in the original Greek text of this letter is Παῦλος, which is Greek for Paul. Some modern translations will add a preposition such as “from” there in order to clarify what is meant. This is roughly the equivalent to the “from” address that we put on the outside of an envelope that we mail, or the from address that appears at the top of an email.
The very next phrase in the Greek is δοῦλος Χριστοῦ Ἰησοῦ, which translates to “a bondservant of Christ Jesus”. In Greek, the word order is often more important then it is in English. In English our word order is grammatically significant, meaning we are forced in to standard patterns such as subject-verb-direct object. Greek allows much greater freedom in word order, so often the order of words reflects the emphasis of the sentence. In this case, Paul appears to be emphasizing that he is a δοῦλος of Christ Jesus.
The word δοῦλος is often translated as “servant”, but has the literal translation of “slave.” This swapping of servant for slave is largely a product of recent American translations and I suspect that it is because slave has a very negative connotation here in America. However I think best translation for this word is probably not slave or servant, but bondservant.
To get a better feel for what this means we need to look back at the Jewish heritage that Paul grew up with. Under Jewish law a slave had to be set free after a certain time of service, but the slave had the option to choose to become a bondservant for life. In Exodus 21:5-6 we read the law regarding bondservants, and the key part of that law is that the servant would do this if the servant loved his master so much that he did not want to go free.
So, in this context, the word δοῦλος is referring to some one that has first chosen to be a bondservant. Second chosen to be a servant for life. Finally, has made that choice out of love and dedication to his master. This is also true of the usage of δοῦλος in other Christian writings from the time. Christians used δοῦλος to mean utter and complete devotion to Christ. 
The next phrase in the Greek is what we see translated as “called to be an apostle.” The verb for to be is not present in the Greek text so there is some variation on how translators will deal with the Greek in order to make the meaning clear to English readers. Paul left out the to be very often in his writings, and it was not required in most cases (like this one) by the Greek language.
The key thing to note in this phrase is that the stress is on called and not apostle. That is, in Paul’s mind, the calling and by implication the caller is what is of importance. Paul stresses this even more in Galatians 1:1 where he in a very verbose manner specifically states out who did and who did not do the calling.
There is much confusion in our modern day about this word, ἀπόστολος that we translate to apostle. Many would confine it only to the original thirteen (the twelve disciples plus Paul). Some would limit it only to the 120 that are mentioned in Acts 1:15, or the 500 that saw the resurrected Christ.
All of those positions ascribe more meaning to the word then the language itself does. In the Bible the term is given freely to anyone that is sent, either by a church, or by God directly. For example, Even though Paul receives his calling in Acts 9:15, he is not called an apostle until after Acts 13:12 when the church at Antioch sends him out. Barnabas, Silas, Apollos, and Timothy are all referred to in the Bible as apostles, none of which fall in to the groups that I previously mentioned.
The point is, the word itself merely means “sent one” or “messenger”, and that sense applies to all Christians, as we were all sent out by Christ into the world to spread his message. That being said, we should be weary of anyone calling themselves an apostle in our modern day because we have added special meaning on to the word, and someone using it of themselves likely does it to show a higher position or value to themselves. Remember Paul identified himself first as a δοῦλος, second as an ἀπόστολος. If anyone was worthy of special uplifting, surely Paul was, and yet he knocked himself down first.
The verse ends with a phrase that tells us more about this “called to be an apostle.” The text says, “separated to the Gospel” or “set apart for the Gospel.” Notice that the text says he is separated to/for and not from. Traditionally we think of separation in negative terms that is we are to be separate from the sins of the word, but here Paul is separated to the Gospel.
The idea that this conveys is that Paul is to do more then just preach the Gospel, he is to live it. That is his very life should preach for him. Everything he does should be inline with the message.
The word, which most translations translate as “gospel” here, is the Greek word “εὐαγγέλιον” which simply means “good news.” It was normally used with regard to good news concerning the Emperor. Here though it is the “good news of God,” or “God’s good news.” A more verbose and dynamic translation could be given as “The gospel which God brings is in fact the gospel about Him.”  That is the news is not only from God, but also about God.
We see here that Paul, who is a model for us to follow (1 Cor. 11:1), first sees himself as a willing and loving slave of Christ. He understands that life is not about him, but about his service and relationship to Christ.
When you live out that truth, you stop trying to better yourself for sake of being better, and start sacrificing yourself for the sake of bringing glory and honor to God. If all Christians everywhere could truly grasp that truth and apply it to their lives, we would see revival in our time such as has not been seen since Acts.
 Thomas R. Schreiner, vol. 6, Romans, Baker exegetical commentary on the New Testament (Grand Rapids, Mich.: Baker Books, 1998), 31.
 William Arndt, Frederick W. Danker and Walter Bauer, A Greek-English Lexicon of the New Testament and Other Early Christian Literature, 3rd ed. (Chicago: University of Chicago Press, 2000), 260.
 Leon Morris, The Epistle to the Romans (Grand Rapids, Mich.; Leicester, England: W.B. Eerdmans; Inter-Varsity Press, 1988), 36-37.
 Note: Paul did have a special authority due to his calling, and that is what is sometimes meant when the Bible uses ἀπόστολος. We must let context drive our understanding and not tradition when we come across this (or any) word.
 Biblical Studies Press, The NET Bible First Edition Notes (Biblical Studies Press, 2006; 2006), Ro 1:1.