There appear to be two editions with the latter not containing the short introductory paragraphs from the elders and Cotton to each other. I did not find either free and in the clear online. They are both in Early English Books Online if you have access to a university that has online access to that service.
Sixteene Questions of Serious and Necessary Consequence, propounded unto Mr. John Cotton of Boston, together with his Answers to each question. London, 1644. [2] 14.
Several Questions of Serious and Necessary Consequences, propounded by the Teaching Elders, unto Mr. John Cotton, of Boston, with his Answers. London, 1647. [2] 10.
One of the longest answers (taking up 5 1/2 pages of the 14 page tract) is to the thirteenth question:
Whether evidencing Justification by Sanctification be a building my Justification on my Sanctification: or a going on in a Covenant of Works.

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Chris Coldwell, Lakewood Presbyterian Church (PCA), Dallas, Texas.
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