SB 7.1.13

atraivodāhṛtaḥ pūrvam
 itihāsaḥ surarṣiṇā
prītyā mahā-kratau rājan
 pṛcchate ’jāta-śatrave
Synonyms: 
atra — in this connection; eva — certainly; udāhṛtaḥ — was recited; pūrvam — previously; itihāsaḥ — an old story; sura-ṛṣiṇā — by the great sage Nārada; prītyā — with joy; mahā-kratau — at the great Rājasūya sacrifice; rājan — O King; pṛcchate — to the inquiring; ajāta-śatrave — Mahārāja Yudhiṣṭhira, who had no enemy.
Translation: 
Formerly, O King, when Mahārāja Yudhiṣṭhira was performing the Rājasūya sacrifice, the great sage Nārada, responding to his inquiry, recited historical facts showing how the Supreme Personality of Godhead is always impartial, even when killing demons. In this regard he gave a vivid example.
Purport: 

This relates to how the Lord exhibited His impartiality even when killing Śiśupāla in the arena of the Rājasūya yajña performed by Mahārāja Yudhiṣṭhira.