The Perfect expresses a completed action.
1) In reference to time, such an action may be:
1a) one just completed from the standpoint of the present
"I have come" to tell you the news
1b) one completed in the more or less distant past
in the beginning God "created"
"I was (once) young" and "I have (now) grown old" but
"I have not seen" a righteous man forsaken
1c) one already completed from the point of view of another
God saw everything that "he had made"
1d) one completed from the point of view of another action
I will draw for thy camels also until "they have done"
2) The perfect is often used where the present is employed in
2a) in the case of general truths or actions of frequent
occurrence--truths or actions which have been often
experienced or observed
the grass "withereth"
the sparrow "findeth" a house
2b) an action or attitude of the past may be continued into
"I stretch out" my hands to thee
"thou never forsakest" those who seek thee
2c) the perfect of intransitive verbs is used where English
uses the present; The perfect in Hebrew in such a case
emphasises a condition which has come into "complete
existence" and realisation
"I know" thou wilt be king
"I hate" all workers of iniquity
2d) Sometimes in Hebrew, future events are conceived so
vividly and so realistically that they are regarded as
Having virtually taken place and are described by the
2d1) in promises, threats and language of contracts
the field "give I" thee
and if not, "I will take it"
2d2) prophetic language
my people "is gone into captivity"
(i.e. shall assuredly go).