"Paul, a servant of Jesus Christ, called to be an apostle, separated unto the gospel of God."
"The apostle declares his name and his position of authority. Speaking as the messenger of Christ, he spake, as he spake, as one having authority, and not as an ordinary teacher.
First, it was not unusual, among the Jews, to change the name of a person in consequence of some remarkable event, as in the case of Abraham and Jacob, Genesis 17:5; 32:28; or when he was advanced to some new office or dignity, Genesis 41:45; Daniel 1:6, 7; so that a new name is sometimes equivalent to a new dignity, Revelation 2:17, it may be supposed that the apostle received the name of Paul, when called to the office of an apostle.
Second, as it was very common for those Jews who had much intercourse with the heathen to bear two names, one Jewish and the other Greek or Roman, which names were sometimes entirely distinct, as Hillel and Pollio, sometimes nearly related as Silas and Silvanus, it is very probable that this was the case with the apostle. He was called Saul among the Jews, and Paul among the Gentiles; and as he was the Apostle of the Gentiles, the latter name became his common designation.
In regards to Paul calling himself a servant of Jesus Christ the following is worthy of consideration: 'It has also been properly remarked, that as the expression, servant of Christ, implies implicit obedience and subjection, it supposes the Divine authority of the Redeemer. That is, we find the apostle denying that he was the servant of men, rejecting all human authority as it regards matters of faith and duty, and yet professing the most absolute subjection of conscience and reason to the authority of Jesus Christ.'
In regards to Paul calling himself an apostle the following should be considered: 'Paul was not only a servant of Christ, but by Divine appointment an apostle. This idea is included in the word κλητός; which means not only called, but chosen, appointed; and the κλῆσις, or vocation, as well of believers to grace and salvation, as of the apostles to their office is uniformly ascribed to God or Christ; see Galatians 1:1; 1 Corinthians 1:1; Titus 1:1; Galatians 1:1. As the immediate call of Christ was one of the essential requisites of an apostle, Paul means to assert in the use of the word κλητός that he was neither self-appointed nor chosen by men to that sacred office.'
Finally, the divine origin of the gospel is asserted in calling it the gospel of God. It is the glad annunciation which God makes to men of the pardon of sin, of restoration to his favor, of the renovation of their nature, of the resurrection of the body, and of eternal life."
Notes from Commentary on the Epistle to the Romans By Charles Hodge, an American Presbyterian theologian, who was ordained in 1821 and taught at Princeton for almost his whole life
NOTE: There are those in our generation who assume the role and take the title of apostle and many of them are women. There is no hint of any kind that a woman was to ever be an apostle in all of scripture. Therefore their claim must be considered spurious since the scriptures also teach that a woman is not to teach or usurp authority over a man, and apostles teach men and are given authority over men. The only instructions in the New Testament for women concerning their call to teach is for the older women to teach the younger women. For a woman to teach any man in the body of Christ is to usurp authority given by God alone. This applies in the home also since the wife is to obey her husband in ALL THINGS according to the scriptures. Further if she has a question she is to keep silence in the church and ask her husband when they get home. To allow a woman to teach or usurp men in the body is to partake of this sin and violates the word of God.
WORD STUDIES ON THIS VERSE
Paul - Greek Paulos meaning little
Servant - Greek doulos meaning a slave or bondsman
Apostle - Greek apostolos meaning a delegate, ambassador or messenger
Separated – Greek aphorizo meaning appointed
Gospel - Greek euangelion meaning gospel or a good message
God - Greek Theos meaning a deity, the supreme divinity, very exceeding God
Note and Word Studies by C R Lord