The word “apostle” means sent one, and when the Lord “commanded” and “sent” the twelve forth (Mt.10:5), they were sent forth by the commandment of God (John 12:49). Since Paul knew not everyone accepted his apostleship, he asserted that he too was an apostle “by the commandment of God” (1:1). This made his apostleship of equal authority with that of the twelve.
But if God had already commanded and sent out 12 apostles, why send out another? It’s not like they were sent to different groups of people, they were all sent to “all nations” (Lu.24:47 cf. Rom.1:5). But the 12 didn’t reach all nations, because Israel, the first nation they were sent to (Lu.24:47) refused to believe, and they couldn’t go to the rest of the nations until the children of Israel were “filled” (Mark 7:27). So God sent another apostle to all nations.
But this means God had to introduce a new program as well as a new apostle. The old plan was to get Israel saved and let them reach all nations as God’s priests. The fact that all nations today have been reached with the gospel of God proves God started a new plan. That’s why Paul told the Corinthian Gentiles that their salvation proved his apostleship. Since they were saved and Israel wasn’t, it proved he was a new apostle with a new message.
When Paul says he was an apostle “by the commandment of God our Saviour,” this shows Paul was also given a new message. In time past, God was the Savior of the Jews only (Isa.49:26), and that didn’t change with the preaching of the 12 (Acts 5:30,31). It changed “in due time” with preaching that was committed to Paul (Tit.1:2,3), when “God our Saviour” said He would “have all men to be saved” (ITim.2:3-7).
Paul also claimed he was an apostle of the Lord Jesus (1:1) who sent him (Acts 26:17) for the same reason God sent him, to offer “forgiveness of sins” (v.18) to all nations.
When Paul says Christ is “our hope,” this is different than when we as Gentiles had “no hope” in time past (Eph.2:11,12).
In his first epistle in Scripture, Paul also introduced himself as a “servant” (Rom.1:1) to let us know the kind of apostle he’d be, one that wasn’t afraid to get involved in the work of the ministry. He also introduced himself as a servant to the Philippians (1:1), knowing that if they’d adopt a servant’s heart it would fix their pride issues, specially when he reminded them their Savior became a servant (2:5-7). He also introduced himself as a servant to Titus (1:1) for that strong leader needed to be reminded that a good leader must be a good servant.
This letter was written to Timothy (1:2), a more timid man than Titus (I Cor. 16:10 cf. IICor.7:14,15). Paul writes to him about his mother, his grandmother, and his tears (IITim. 1:4,5). But this mamma’s boy was respected in two churches (Acts 16:1-3). Born and raised in Lystra, where he saw Paul stoned, he still agreed to go with Paul when the apostle asked him to, even though it meant having to undergo a painful adult circumcision (v.3 cf. Gen.34:25).
All of this proves that God can use you, even if you’re timid. Timothy fit in at Philippi better than Titus (Phil.2:19) since the church started with women (Acts 16:11,12), and about the only members named are women (Phil.4:2), leading us to believe the church consisted mostly of women. Well, Timothy was raised by women!
When Paul calls him “mine own son in the faith” (1:2), that means Lois and Eunice might have raised him in the Jewish faith, but Paul led him to the Lord. If you are raising your kids in the faith, it might take someone else to reach them.
Paul offers grace and peace to the churches he wrote to, but “mercy” to the pastors (ITim.1:1; IITi.1:1; Tit.1:1). He may have been referring to the kind of mercy that enabled him to remain single (ICor.7:25), or the food and clothing kind (IITim.1:16) when churches didn’t supply their needs, or the kind of mercy in physical illness that servants of the Lord like Epaphroditus had (Phil.2:25-27).