Or a thing; 3.

Or a quality, property, or attribute.
If you take the first, then you admit the contradiction; if either of the latter two, you have not three Persons and one God, but three Persons having equal shares in one thing, or three with the same attributes, that is, three Gods.

Sherlock does not meet this.
Let me repeat the difficulty, if possible, more clearly.

The argument of the philosophic Unitarians, as Wissowatius, who, mistaken as they were, are not to be confounded with their degenerate successors, the Priestleyans and Belshamites, may be thus expressed.

By the term, God, we can only conceive you to suppose one or other of three meanings.
1.