Various Greek prepositions (words like "into," "after," "from," etc.) may take objects of a specific case (genitive, dative, and accusative) only. However, several important ones take objects in different cases The meaning of the preposition phrase changes with the form of the object. (See this article for more detail.) Whether the preposition takes a single case or several, below are the general sense of how the Greek works.

• A genitive object means a movement away from something or a position away from something else. The time sense of a genitive object is that the event occurred within a specified time.
• A dative object implies no movement but in a fixed position. Event occurs at a specified time or while the action was being performed.
• An accusative object indicates movement towards something or a position reached as a result of that movement. Event may show the amount of time

πρεσβυτέρων [2 verses](adj pl masc gen irreg_comp) "Elders" is from presbyteros, which means "old men", "elder", "old age", "ambassador", in comparative and superlative., of things, "more or most important", "taking precedence".  -- "Elders" is a Greek adjective means "old men", "elder", "old age", "ambassador", in comparative and superlative., of things, "more or most important", "taking precedence". 

ἀράτω [2 verses](verb 3rd sg aor imperat act) "Take up" is from aeirô, which means "to lift up", "to raise up", "to take up", ""to exalt," and "to remove." -- "Take up" is a verb that means "to lift up", "to raise up", "to take up", "to exalt," and "to remove." It is also in the form of a third party command, so "he must". 

πρὶν [4 verses](adv/conj)"Before" is from prin, which means "before", "until," "sooner", "formerly," and "hitherto."  - "Before" is an uncommon Greek adverb that means "before", "until," "sooner", "formerly," and "hitherto." This verb means "until" with a finite verb and "before" with an infinitive. Jesus only used it four times.

πρὸ [12 verses](prep) "Before" is pro, which means (of place) "before," "in front of," (of time) "before," (of preference) "before" in time, "rather than," "more than," and so on.-- The Greek word translated as "before" means (of place) "before," "in front of," (of time) "before," (of preference), "rather than," "more than," and so on.