Hariścandra was certainly very much attached to his son. Because of this affection, he asked the demigod Varuṇa to wait. Thus Varuṇa waited and waited for the time to come.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
इति पुत्रानुरागेण स्नेहयन्त्रितचेतसा । कालं वञ्चयता तं तमुक्तो देवस्तमैक्षत
iti putrānurāgeṇa snehayantritacetasā | kālaṃ vañcayatā taṃ tamukto devastamaikṣata
SB 9.7.15