Brihat Parashara Hora Shastra
अवताराण्यनेकानि ह्यजस्य परमात्मनः। जीवानां कर्मफलदो ग्रहरूपी जनार्दनः॥ ३॥
The unborn Lord has many incarnations. He has incarnated, as the 9 (Nava) Grahas to bestow on the living beings the results due to their Karmas.
english translation
avatArANyanekAni hyajasya paramAtmanaH। jIvAnAM karmaphalado graharUpI janArdanaH॥ 3॥
hk transliteration by Sanscript