If we consider Paul’s general theme in this chapter, the first part of this verse implies “It is not the fact I am preaching the gospel that in itself gives me the reason for boasting.” The rest of the verse then explains that to preach the gospel is an obligation, not a matter of free choice.

The first For may be expanded to “The truth is” or “Truly.”

For ground of boasting see comments on verse 15.

The clause For necessity is laid upon me may be rendered as “God has commanded me to do so.”

Is laid refers by implication to the action of God in calling Paul to be an apostle (see 1.1).

Woe to me is more than an interjection expressing sorrow; it refers implicitly to future judgment. In that case one can translate this as “How terrible it will be for me.” Paul does not use this expression elsewhere, but the translator may compare, for example, Matt 23.13-23; Luke 6.24-26; and Rev 18.10-19.

Quoted with permission from Ellingworth, Paul and Hatton, Howard A. A Handbook on Paul’s First Letter to the Corinthians, 2nd edition. (UBS Handbook Series). New York: UBS, 1985/1994. For this and other handbooks for translators see here .