Many interpreters of the Bible make a big deal about the "durative" aspect of the present tense. They'll point to a passage like John 3:16 and say, "the word 'believe' is a present participle and therefore it means 'continued belief.'" However, this type of interpretation is faulty in many ways. For starters, the present continuous is a tense used of something that already started in the past. A thing cannot start and continue at the same time. So the question is: "When did they begin to believe?" One second ago, one year ago, a lifetime ago? How long exactly does a person need to believe to receive eternal life?
So, what is implied, if anything, by "durative" action? In Section 1852 of Herbert Weir Smyth's "A Greek Grammar for Colleges," he says, "Continued action is incomplete: hence nothing is stated as to the conclusion. Thus φεύγει he flees does not state whether or not the subject succeeded in escaping." Just because a verb is in the present tense doesn't imply that the action "continues forever" or a person "perseveres to the end."
And why exactly is the present tense characterized as durative anyway? In Section 70 of D. B. Monro's "Homeric Grammar," he says the following: "The present is not a space of time, but a point; what is present therefore is not (generally speaking) a whole action or event, but the fact that it is in course of happening. So in English we usually say, not I write now, but I am writing now. The mere effort of regarding an action as in present time almost obliges us to give it a progressive character."
Finally, is the the present tense always "durative"? In Section 1853, Smyth says, "The present stem may denote the simple action of the verb in present time without regard to its continuance; as θαυμάζω I am seized with astonishment, ἀστράπτει it lightens (once or continually), δίδωμι I make a present. This is called the aoristic present. On inceptive verbs, see 526." On page 866 of A. T. Robertson's "A Grammar of the Greek New Testament in the Light of Historical Research," he says, "The Gnomic Present. This is the aorist present that is timeless in reality, true of all time." And this is exactly how the present participle is working in John 3:16 with the gnomic idea being signified by the use of πᾶς in the expression "everyone who believes."