SB 6.2.8

etenaiva hy aghono ’sya
 kṛtaṁ syād agha-niṣkṛtam
yadā nārāyaṇāyeti
 jagāda catur-akṣaram
Synonyms: 
etena — by this (chanting); eva — indeed; hi — certainly; aghonaḥ — who possesses sinful reactions; asya — of this (Ajāmila); kṛtam — performed; syāt — is; agha — of sins; niṣkṛtam — complete atonement; yadā — when; nārāyaṇa — O Nārāyaṇa (the name of his son); āya — please come; iti — thus; jagāda — he chanted; catuḥ-akṣaram — the four syllables (nā-rā-ya-ṇa).
Translation: 
The Viṣṇudūtas continued: Even previously, while eating and at other times, this Ajāmila would call his son, saying, “My dear Nārāyaṇa, please come here.” Although calling the name of his son, he nevertheless uttered the four syllables nā-rā-ya-ṇa. Simply by chanting the name of Nārāyaṇa in this way, he sufficiently atoned for the sinful reactions of millions of lives.
Purport: 

Previously, when engaged in sinful activities to maintain his family, Ajāmila chanted the name of Nārāyaṇa without offenses. To chant the holy name of the Lord just to counteract one’s sinful activities, or to commit sinful activities on the strength of chanting the holy name, is offensive (nāmno balād yasya hi pāpa-buddhiḥ). But although Ajāmila engaged in sinful activities, he never chanted the holy name of Nārāyaṇa to counteract them; he simply chanted the name Nārāyaṇa to call his son. Therefore his chanting was effective. Because of chanting the holy name of Nārāyaṇa in this way, he had already vanquished the accumulated sinful reactions of many, many lives. In the beginning he was pure, but although he later committed many sinful acts, he was offenseless because he did not chant the holy name of Nārāyaṇa to counteract them. One who always chants the holy name of the Lord without offenses is always pure. As confirmed in this verse Ajāmila was already sinless, and because he chanted the name of Nārāyaṇa he remained sinless. It did not matter that he was calling his son; the name itself was effective.