Valmiki Ramayana Bala Kanda Sarga 14 Shloka 55

तत: there after, राजा king Dasaratha, पापापहम् capable of removing sins, स्वर्नयनम् leading to heaven, पार्थिवर्षभै: for monarchs, दुष्करम् incapable of being done, अनुत्तमम् greatest, यज्ञम् sacrifice, प्राप्य having performed, प्रीतमना: cheerful heart.

Sacrifice destroys sins. It leads to heaven. It is incapable of being done by other monarchs. King Dasaratha was very much pleased after performing this great sacrifice.