A.T. Robertson Commentary 2 Corinthians 10:16

"so as to preach the gospel even unto the parts beyond you, [and] not to glory in another`s province in regard of things ready to our hand." — 2 Corinthians 10:16 (ASV)

Even unto the parts beyond you (εις τα υπερεκεινα υμων). Compound adverb (υπερ, εκεινα, beyond those places) used as preposition. Found only here and in ecclesiastical writers.

Things ready to our hand (τα ετοιμα). He had a plenty besides that he could use.