Full Idea
If an object has a certain property essentially, then it follows that the object has the property necessarily (if it exists).
Gist of Idea
If an object exists, then its essential properties are necessary
Source
Kathrin Koslicki (Essence, Necessity and Explanation [2012], 13.2)
Book Reference
'Contemporary Aristotelian Metaphysics', ed/tr. Tahko,Tuomas [CUP 2012], p.190
A Reaction
She is citing Fine, who says that the converse (necessity implying essence) is false. I agree with that. I also willing to challenge the first bit. I suspect an object can retain identity and lose essence. Coma patient; broken clock; aged athlete.