Brihat Parashara Hora Shastra
गुरुणा केवलेनैव सर्वविद् ग्रन्थकृत् तथा । वेदवेदान्तविच्चापि न वाग्मी शाब्दकोऽपि सन् ॥ ४२॥
Śukr will make one an ordinary writer, while Budh will indicate, that the writing skills are less than those of an ordinary writer. Should Guru be alone, one will be a knower of everything, be a writer and be versed in Vedas and Vedanta philosophy, but not an oratorian, or a grammarian.
english translation
guruNA kevalenaiva sarvavid granthakRt tathA । vedavedAntaviccApi na vAgmI zAbdako'pi san ॥ 42॥
hk transliteration by Sanscript