The introduction to B.H. McLean's new Greek textbook nicely explains why I think all pastors should take at least two years of Biblical Greek (or acquire a reading knowledge of Greek by hook or by crook some other way):
Given the fact that the New Testament is written in Hellenistic Greek, it follows that those who desire a deeper understanding of its message must strive to attain a thorough knowledge of this language. Learning Greek requires patience, perseverance, and the willingness to struggle. But those who are committed to understanding the Christian gospel should not view this task as an imposition, but as a blessing, for with it comes a deeper knowledge of Scriptures.
There can be no doubt that the ability to read and interpret the New Testament in its original language is a central component of the Reformed tradition. Indeed, all theologians since the Renaissance, including Erasmus, Calvin, and Luther, emphasized the importance of studying the Bible in its original languages. . . . [W]hile mastering Hellenistic Greek may not be a realistic goal for every student of theology, total unfamiliarity with the original language of the New Testament is indefensible for theologians and seminarians. After all, there is probably no rabbi who cannot read the Tanakh in the original Hebrew, or imam who cannot read the Qur'an in the original Arabic language.
But Christians should not approach the study of Hellenistic Greek as if it were a trial or obstacle to overcome. Those who really commit themselves to the regular lifelong study of the Greek New Testament will come to know the true joy of being led through and beyond, its words to a lived, faithful, transformative relationship with the living God. Indeed, we must not forget that patience in the study of sacred Greek Scriptures nurtures patience in the grace of God!
- B.H. McLean, New Testament Greek: An Introduction (New York: Cambridge University Press, 2011)