What is this ‘gospel’ for which Paul is willing to glory in being a slave? What gospel would make Paul happy to lose everything in order to share it? First, it is worth reflecting on the word itself. ‘Gospel’ — euangeloi — is literally ‘good herald.’ In the first century, if on a far-flung battlefield an emperor won a great victory which secured his peace and established his authority, he would send heralds — angeloi — to declare his victory, peace and authority. Put most simply, the gospel is an announcement — a declaration. The gospel is not advice to be followed; it is news, good (eu) news about what has been done.
The apostle Paul is the herald of this announcement. It is a good reminder that the gospel is not Paul’s; it did not originate with him and he did not claim the authority to craft it. Rather, it is ‘of God’ (v 1). We, like Paul, are not at liberty to reshape it to sound more appealing in our day, nor to domesticate it to be more comfortable for our lives.
– Tim Keller