There are five cases in New Testament Greek that you should remember by heart:
(1) nominative (case of the subject)
(2) genitive (or possessive)
(3) dative (conjunctive)
(4) accusative (case of the object)
(5) vocative (used in direct address).
Τhe nominative is the case of the subject. “A verb must agree with nominative case in number and person” (The first Concord). Nouns are of the third person.
When the subject is a personal pronoun, it is implied in the form of the verb, and is not separately expressed unless emphatic. In the third person singular, the omitted subject will be he, she, or it, and is to be learned from the connexion.
The genitive often denotes possession, and in English has the sign of.
The genitive, dative, or accusative may be governed by prepositions, in conformity with the general idea of the several cases: the genitive signifying origin – from ; the dative, association – in, or with ; the accusative, approach – toward, to, into