Canto 3 -
Araṇya-kāṇḍa
Chapter 71: Kabandha’s Past Life
Text 3.71.6
यदा छित्त्वा भुजौ रामस्त्वां दहेद्विजने वने।
तदा त्वं प्राप्स्यसे रूपं स्वमेव विपुलं शुभम्॥
yadā chittvā bhujau rāmas tvāṁ dahed vijane vane
tadā tvaṁ prāpsyase rūpaṁ svam eva vipulaṁ śubham
yadā = when; chittvā = cuts; bhujau = your arms; rāmaḥ = Rāma; tvām = you; dahet = and burns; vijane = in the lonely; vane = forest; tadā tvam prāpsyase = you will attain; rūpam = form; svam eva = your original; vipulam = which is excellent; śubham = and beautiful.
When Rāma cuts your arms and burns you in the lonely forest, you will attain your original form which is excellent and beautiful.
Then why did he attain the form of a headless trunk? He answers this question in the next verse.