Canto 3 -
Araṇya-kāṇḍa
Chapter 65: Lakṣmaṇa Consoles Rāmacandra
Text 3.65.15

न चेत्साम्ना प्रदास्यन्ति पत्नीं ते त्रिदशेश्वराः।
कोसलेन्द्र ततः पश्चात्प्राप्तकालं करिष्यसि॥

na cet sāmnā pradāsyanti patnīṁ te tridaśeśvarāḥ
kosalendra tataḥ paścāt prāpta-kālaṁ kariṣyasi

na = not; cet = if; sāmnā = through conciliation; pradāsyanti = do give; patnīm = Your wife; te = You; tridaśa-īśvarāḥ = the lords of the demigods; kosala-indra = O Lord of Kosala; tataḥ paścāt = then; prāpta-kālam kariṣyasi = You can do the needful at the right time.

If the lords of the demigods do not give You Your wife through conciliation, O Lord of Kosala, You can then do the needful at the right time.

“You can do the needful at the right time” means “You can punish when it is time to punish.”1

Lakṣmaṇa clarifies this in the next verse. 

1 Rāmāyaṇa-bhūṣaṇa: prāptaś caturthopāya-kālo yasmin karmaṇi tat tathā.