Shiva Purana
अश्वत्थामा ततो ज्ञात्वा वृत्तमेतच्छिवांशजः ॥ शैवन्न विव्यथे किञ्चिच्छिवेच्छातुष्टधीर्मुने ॥ ३२ ॥
O sage, knowing that this happened by the influence of Śiva, Aśvatthāman, born of Śiva’s part and delighted in heart at Śiva’s wish, was not at all sorry.
english translation
azvatthAmA tato jJAtvA vRttametacchivAMzajaH ॥ zaivanna vivyathe kiJcicchivecchAtuSTadhIrmune ॥ 32 ॥
hk transliteration by Sanscript