Attraction is the process by which a relative pronoun

Relative pronoun

A relative pronoun is a pronoun that marks a relative clause within a larger sentence. It is called a relative pronoun because it relates the relative clause to the noun that it modifies. In English, the relative pronouns are: who, whom, whose, whosever, whosesoever, which, and, in some...

 takes on—that is, is "attracted to" -- the case

Declension

In linguistics, declension is the inflection of nouns, pronouns, adjectives, and articles to indicate number , case , and gender...

 of its antecedent

Antecedent (grammar)

In grammar, an antecedent is a noun, noun phrase, or clause to which an anaphor refers in a coreference. For example, in the passage "I did not see John because he wasn't there", "John" is the antecedent of the anaphor "he"; together "John" and "he" are called a coreference because they both refer...

, rather than having the case appropriate to its function in the relative clause. For example, in this English sentence, the relative pronoun has the appropriate case, namely, the accusative

Accusative case

The accusative case of a noun is the grammatical case used to mark the direct object of a transitive verb. The same case is used in many languages for the objects of prepositions...

:

This is the boss of the man whom I met yesterday.

This sentence, on the other hand, shows attraction:

This is the boss of the man whose I met yesterday.

Because the antecedent, "[of] the man", is possessive, the relative pronoun has become possessive too. Attraction is a theoretical process in standard English

English language

English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

, but is common in the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 of the Septuagint and also occurs in the New Testament

New Testament

The New Testament is the second major division of the Christian biblical canon, the first such division being the much longer Old Testament....

.