“This is the very nature of this world” is implied in each of the examples cited by Lakṣmaṇa [from this verse].

After Yayāti reached Svarga, Indra, contaminated by jealousy, asked him, “Who is the best in your kingdom?” As a speaker of truth, Yayāti said, “I alone.” Indra [then] threw him [out of Svarga] by saying, “You who praise yourself are unfit for Svarga.” This is well known from the Purāṇas.

By referring to Yayāti as Nahuṣa’s son, it is hinted that Yayāti was as immoral as Nahuṣa because while remembering Śacī, Indra’s wife, Nahuṣa told the seven sages, whom he had made into his palanquin carriers, “Go quickly, go quickly!”¹ Agastya then cursed him, “Become a snake!” Nahuṣa then became a snake.

NOTE. In Śrīmad-Bhāgavatam 6.13.10-16, Nahuṣa’s history is given as follows:

śrī-śuka uvāca
evaṁ sañcodito viprair marutvān ahanad ripum
brahma-hatyā hate tasminn āsasāda vṛṣākapim

Śrī Śukadeva Gosvāmī said: Encouraged by the words of the sages, Indra killed Vṛtrāsura, and when he was killed the sinful reaction for killing a brāhmaṇa [brahma-hatyā] certainly took shelter of Indra.

tayendraḥ smāsahat tāpaṁ nirvṛtir nāmum āviśat
hrīmantaṁ vācyatāṁ prāptaṁ sukhayanty api no guṇāḥ

Following the advice of the demigods, Indra killed Vṛtrāsura, and he suffered because of this sinful killing. Although the other demigods were happy, he could not derive happiness from the killing of Vṛtrāsura. Indra’s other good qualities, such as tolerance and opulence, could not help him in his grief.

tāṁ dadarśānudhāvantīṁ cāṇḍālīm iva rūpiṇīm
jarayā vepamānāṅgīṁ yakṣma-grastām asṛk-paṭām
vikīrya palitān keśāṁs tiṣṭha tiṣṭheti bhāṣiṇīm
mīna-gandhy-asu-gandhena kurvatīṁ mārga-dūṣaṇam

Indra saw personified sinful reaction chasing him, appearing like a caṇḍāla woman, a woman of the lowest class. She seemed very old, and all the limbs of her body trembled. Because she was afflicted with tuberculosis, her body and garments were covered with blood. Breathing an unbearable fishy odor that polluted the entire street, she called to Indra, “Wait! Wait!”

nabho gato diśaḥ sarvāḥ sahasrākṣo viśāmpate
prāg-udīcīṁ diśaṁ tūrṇaṁ praviṣṭo nṛpa mānasam

O King, Indra first fled to the sky, but there also he saw the woman of personified sin chasing him. This witch followed him wherever he went. At last he very quickly went to the northeast and entered the Mānasa-sarovara Lake.

sa āvasat puṣkara-nāla-tantūn
alabdha-bhogo yad ihāgni-dūtaḥ
varṣāṇi sāhasram alakṣito ’ntaḥ
sañcintayan brahma-vadhād vimokṣam

Always thinking of how he could be relieved from the sinful reaction for killing a brāhmaṇa, King Indra, invisible to everyone, lived in the lake for one thousand years in the subtle fibers of the stem of a lotus. The fire-god used to bring him his share of all yajñas, but because the fire-god was afraid to enter the water, Indra was practically starving.

tāvat triṇākaṁ nahuṣaḥ śaśāsa
vidyā-tapo-yoga-balānubhāvaḥ
sa sampad-aiśvarya-madāndha-buddhir
nītas tiraścāṁ gatim indra-patnyā

As long as King Indra lived in the water, wrapped in the stem of the lotus, Nahuṣa was equipped with the ability to rule the heavenly kingdom, due to his knowledge, austerity and mystic power. Nahuṣa, however, blinded and maddened by power and opulence, made undesirable proposals to Indra’s wife with a desire to enjoy her. Thus Nahuṣa was cursed by a brāhmaṇa and later became a snake.