Canto 3 -
Araṇya-kāṇḍa
Chapter 43: Sītā Sees the Magical Deer
Text 3.43.48-49

अप्रमत्तेन ते भाव्यमाश्रमस्थेन सीतया॥

यावत्पृषतमेकेन सायकेन निहन्म्यहम्।
हत्वैतच्चर्म चादाय शीघ्रमेष्यामि लक्ष्मण॥

apramattena te bhāvyam āśramasthena sītayā

yāvat pṛṣatam ekena sāyakena nihanmy aham
hatvaitac carma cādāya śīghram eṣyāmi lakṣmaṇa

apramattena = attentive; te = You; bhāvyam = should be; āśramasthena = in the āśrama; sītayā = on account of Sītā; yāvat = until; pṛṣatam = the deer; ekena = with a single; sāyakena = arrow; nihanmi = kill; aham = I; hatvā = after killing [it]; etat carma ca = its skin; ādāya = I will take; śīghram = and quickly; eṣyāmi = come; lakṣmaṇa = Lakṣmaṇa.

Lakṣmaṇa, You should be attentive in the āśrama on account of Sītā until I kill the deer with a single arrow.1 After killing [it] I will take its skin and quickly come!

Lord Rāma wanted Lakṣmaṇa to be undistracted in the āśrama while protecting Sītā-devī.

1 Rāmāyaṇa-bhūṣaṇa: sītayā hetu-bhūtayā.