Praying to Sun god (Suryopasana) has many benefits described in Vedas. According to Rig Veda, Book 1, Hymn 50, Surya is the remover of heart disease and yellowness of body.
उद्यन्नद्य मित्रमह आरोहन्नुत्तरां दिवम |
हर्द्रोगं ममसूर्य हरिमाणं च नाशय ||
11 Rising this day, O rich in friends, ascending to the loftier heaven,
Sūrya remove my heart'...
I would like to add this answer of mine as suplimentory to above one.
Various benifits of Suryopasana or sun worship also are described in Suryopanishad (सूर्योपनिषद)
Which is part of Atharvveda.
य एतां महाभागः प्रातः पठति स भाग्यवाञ्जायते । पशून्विन्दति । वेदार्थं
लभते । त्रिकालमेतज्जप्त्वा क्रतुशतफलमवाप्नोति । यो हस्तादित्ये जपति स
महामृत्युं तरति ...
I agree with what Pradip Gangopadhyay stated in his answer that Aum is the starting point of all mantras as has been pointed out in the purport of the following verse SB 6.5.26:
At Nārāyaṇa-saras, the second group of sons performed penances in the
same way as the first. They bathed in the holy water, and by its touch
all the dirty material desires in ...
Om is usually the starting point of most mantras. The reason is given below.
The syllable Om is the root from which the Vedas have sprung. (Every
rite, therefore, should commence with the utterance of that syllable
of vast import). Of him who has uttered for him the syllables Om,
Namas, Swaha, Svadha, and Vashat, and who has according to the extent