अन्वयः

वीर: mighty warrior, महाकपि: great monkey, Hanuman, पैतामहात् by Brahma's, वरात् boon, आत्मानम् his own self, अस्त्रेण by the weapon (given by Brahma), उन्मुक्तम् released, ज्ञात्वा coming to know, यदृच्छया casually (in the expectation of his another objective of seeing Ravana), यन्त्रिण: restrained by ropes, तान् राक्षसान् those rakshasas, मर्षयन् while enduring, तत: after completion of that act, मैथिलीम् सीतां ऋते except Sita (Mythili), लङ्कां पुरीम् the city of Lanka, दग्ध्वा having burnt, रामाय for Rama, प्रियम् welcome tidings, आख्यातुम् to deliver, पुन: आयात् returned again.

M N Dutt

Then knowing that in virtue of the grandsire's boon, he was free, he forgave those Raksasas that were leading him (to Ravana.)

Summary

The heroic Hanuman came to know that he could be released from the entanglements of the weapon granted to him through a boon by Brahma. He allowed himself to be restrained by the rakshasas with the ropes for the sake of achieving his other objective of seeing Ravana. Thereafter, he burnt the whole of Lanka except the place where Sita was and returned to deliver the good news to Rama.

पदच्छेदः

आत्मानं	आत्मन् (२.१)
ज्ञात्वा	ज्ञात्वा (√ज्ञा + क्त्वा)
पैतामहाद्	पैतामह (५.१)
वरात्	वर (५.१)
मर्षयन्	मर्षयत् (√मर्षय् + शतृ, ८.१)
राक्षसान्	राक्षस (२.३)
वीरो	वीर (१.१)
यन्त्रिणस्	यन्त्रिन् (२.३)
तान्	तद् (२.३)
यदृच्छया	यदृच्छा (३.१)

छन्दः

अनुष्टुप् [८]

छन्दोविश्लेषणम्

१	२	३	४	५	६	७	८
अ	स्त्रे	णो	न्मु	ह	मा	त्मा	नं
ज्ञा	त्वा	पै	ता	म	हा	द्व	रात्
म	र्ष	य	न्रा	क्ष	सा	न्वी	रो
य	न्त्रि	ण	स्ता	न्य	दृ	च्छ	या