Text 6]
King Citraketu's Lamentation
9
nārāyaṇāyaṇā devā ṛṣy-ādyās tat-parāyaṇāḥ brahmādyāḥ kecanaiva syuḥ siddho yogya-sukhaṁ labhan
The difference between the  siddhas  and  nārāyaṇa-parāyaṇas  is that direct devotees are called  nārāyaṇa-parāyaṇas  whereas those who perform various types of mystic  yoga  are called  siddhas .
TEXT 6
वृत्रस्तु स कथं पापः सर्वलोकोपतापनः । इत्थं दृढमतिः कृष्ण आसीत् संग्राम उल्लेणे ॥ ६ ॥
vṛtras tu sa kathaṁ pāpaḥ sarva-lokopatāpanaḥ itthaṁ dṛḍha-matiḥ kṛṣṇa āsū saṅgrāma ulbaṇe
vṛtraḥ—Vṛtrāsura; tu—but; saḥ—he; kathaṁ—how; pāpaḥ—although sinful (getting the body of a demon); sarva-loka—of all the three worlds; upatāpanaḥ—the cause of suffering; itthaṁ—such; dṛḍha-matiḥ—firmly fixed intelligence; kṛṣṇe—in Kṛṣṇa; āsū—there was; saṅgrāme ulbaṇe—in the great blazing fire of battle.
TRANSLATION
Vṛtrāsura was situated in the blazing fire of battle and was an infamous, sinful demon, always engaged in giving troubles and anxieties to others. How could such a demon become so greatly Kṛṣṇa conscious?
PURPORT
It has been described that a  nārāyaṇa-parāyaṇa , a pure devotee, is rarely found even among millions and millions of persons. Therefore Parikṣit Mahārāja was surprised that Vṛtrāsura, whose purpose was to give trouble and anxiety to others, was one of these devotees, even on a battlefield. What was the reason for Vṛtrāsura's advancement?