I get a little worried when I hear people talk about contextualizing the gospel. If, by contextualization, we mean merely that we change ourselves by means of self-sacrifice, then that's okay. Paul himself claimed to be all things to all people. It's important to note that Paul is the one doing the changing here; not the gospel. If, by contextualization, we mean that we have to change the content of the gospel, then that is not okay. In fact, it's apostasy. Paul said that if even he himself or an angel from heaven preach a gospel contrary to what he proclaimed, let that one be anathema, cursed (Gal 1:8). There is only one gospel.
The gospel transcends time and culture. The good news that the crucified and risen Christ Jesus is now the Lord of heaven and earth is relevant to all people everywhere. It is always a summons to the obedience of faith no matter the context. Whether in the first century or the twenty-first century, the gospel is the same. Whether in Jerusalem, New York, Mexico, Darfur, or India, the gospel is the same.
Why is this so important? Because the gospel is the power of God for salvation to everyone who has faith and because in the gospel, God's righteousness is revealed (Rom 1:16-17). To change the content of the gospel is to strip it of it's power. Indeed, it is to strip it of that which makes it gospel in the first place. To change the content of the gospel is to make it no gospel at all!
For these reasons Christians must be absolutely clear about the content of the gospel. It is of first importance (1 Cor 15:3). No matter who you are or where you live, The Jesus who died for our sins according to the scriptures is Lord, and God raised him from the dead!