Of course, those on the works treadmill can never really spell out exactly what the whole counsel of God is or how it should be defined apart from grace. Those who do will only be able to give you an opinion and guesswork based on a very limited perspective and likely an inaccurate one.
Right before Paul mentioned this phrase, he described what it was that the whole counsel of God revolves around, and the ministry he received from which he was called to testify about. Spoiler alert: It was the gospel of the grace of God.