In lines 1-26 of Book I of John Milton's Paradise Lost, how is the speaker ambitious and how is the speaker humble?

The speaker of the first 26 lines of John Milton’s
Paradise Lost is clearly meant to be identified with Milton himself. The
speaker displays an intriguing combination of ambition and humility, as befits a mere human being
who is attempting to explain one of the most important events in all of human
history.

Milton’s ambitiousness is implied or overtly stated in a
number of ways in these lines. Some examples of his ambitiousness include the
following:

1. He chooses a theme already dealt with in the
   Bible and thus runs the risk of appearing to try to “improve upon”
   scripture.


2. He chooses a genre, mode, and style associated with the
   classical epics, some of the most highly respected poems ever
   written.


3. He directly addresses the same “Heav’nly Muse” (1.6) who
   had inspired Moses to write the first five books of the Bible. Milton knew that such an address
   might seem presumptuous to some of his readers.


4. He implicitly
   places compares himself to Moses since he seeks, like Moses, to act as an inspired prophet and
   historian.


5. He explicitly calls his song “adventurous” (1.13), or
   daring.


6. He explicitly proclaims that he intends “with no middle
   flight . . . to soar / Above th’Aonian mount” (1.14-15) – in other words, to surpass the
   achievements of the great writers of classical epics.


7. He announces
   that he intends to pursue “Things unattempted yet in prose or rhyme”
   (1.16).


8. He suggests that the Holy Spirit will recognize in him an
   “upright heart and pure” (1.17).


9. He openly states that he intends
   to explain the workings of “Eternal providence, / And justify [that is, show the justice of] the
   ways of God to men” (1.26).

In 26 lines, then, Milton
reveals enormous spiritual and poetic ambitions.  On the other hand, these 26 lines also imply or
openly reveal a good deal of humility as well.  Examples of such humility include the
following:

1. In speaking of the need for Christ to “Restore
   us” after the fall (1.5), Milton implies that he, like all human beings, is fallen and
   sinful.


2. By invoking the heavenly muse to sing (1.6), Milton
   implies his hope that he will merely be a mouthpiece inspired by
   God.


3. By allowing the muse to choose the exact mode of inspiration
   (1.10-13), Milton implies that he is an essentially passive receptacle of divine
   inspiration.


4. In the very lines in which Milton announces his
   intention to pursue “Things unattempted yet in prose or rhyme” (1.16), he pays sly tribute to an
   earlier Italian poet.


5. In line 1.19, Milton explicitly asks for
   divine instruction.


6. In lines 1.22-23, Milton concedes that his
   physical blindness makes him all the more dependent on divine
   inspiration.


7. In those same lines, Milton implies that he, like all
   human beings, is spiritually dark and needs spiritual support from God. In other words, he
   concedes his sinfulness and imperfection and makes clear that he can achieve nothing without
   God’s help.

For an excellent brief overview of the poem,
please see C. S. Lewis, A Preface to Paradise Lost (Oxford: Oxford
University Press, 1961).