Canto 3 -
Araṇya-kāṇḍa
Chapter 50: Jaṭāyu Challenges Rāvaṇa
Text 3.50.16

सर्पमाशीविषं बद्ध्वा वस्त्रान्ते नावबुध्यसे।
ग्रीवायां प्रतिमुक्तं च कालपाशं न पश्यसि॥

sarpam āśīviṣaṁ baddhvā vastrānte nāvabudhyase
grīvāyāṁ pratimuktaṁ ca kāla-pāśaṁ na paśyasi

sarpam = serpent; āśīviṣam = an āśīviṣa; baddhvā = that you have bound; vastra-ante = to the end of your garment; na avabudhyase = you don’t understand; grīvāyām = around your neck; pratimuktam = tied up; ca = and; kāla-pāśam = the noose of death; na paśyasi = you don’t see.

You don’t understand that you have bound an āśīviṣa serpent to the end of your garment and you don’t see the noose of death tied up around your neck.1

Carrying away Sītā-devī would certainly bring about Rāvaṇa’s death. Jaṭāyu states this in this verse.

Jaṭāyu implies that just as a serpent tied to one’s cloth certainly destroys one, when this lady Sītā is grabbed [by Rāvaṇa] she will destroy him.

1 Āśiviṣa is a kind of venomous snake. Technical note: pratimuktam pratibandhitam.