I don't understand, if the original essence of Hinduism is monotheism and acknowledgement of Brahma as only God (Ishwar), why do Hindus need to incorporate what we would consider polytheistic beliefs and observances? See below from the Vedas:
Yajurveda 40.1:
This entire world is embedded within and managed by the One and Only One Ishwar. Never dare do any injustice or desire riches through unjust means. Instead follow the righteous path and enjoy His bliss. After all He alone is source of all bliss!
Rigveda 10.48.1
Ishwar alone is omnipresent and manager of entire universe. He alone provides victory and eternal cause of world. All souls should look up only to Him in same manner as children look up to their Father. He alone provides for our sustenance and bliss.
Rigveda 10.48.5
Ishwar enlightens the entire world. He alone is undefeated and undying. He alone is the creator of the world. All souls should seek bliss through seeking knowledge and acting thereupon. They should never shun the friendship of Ishwar.
Rigveda 10.49.1
Ishwar alone provides true knowledge to truth seekers. He alone is promoter of knowledge and motivates virtuous people into noble actions to seek bliss. He alone is the creator and manager of the world. Hence never worship anyone else except one and only Ishwar.
Yajurveda 13.4
There is one and only One Creator and Maintainer of the entire world. He alone is sustaining the earth, sky and other heavenly bodies. He is Bliss Himself! He alone deserves to be worshiped by us.
Atharvaveda 13.4.16-21
He is neither two, nor three, nor four, nor five, nor six, nor seven, nor eight, nor nine, nor ten. He is, on contrary, One and Only One. There is no Ishwar except Him. All Devtas reside within Him and are controlled by him. So He alone should be worshiped, none else.
Atharvaveda 10.7.38
Ishwar alone is greatest and worth being worshiped. He is the source of all knowledge and activities.
Yajurveda 32.11
Ishwar resides at each point in universe. No space is devoid of Him. He is self-sustaining and does not need help of any agent, angel, prophet or incarnation to perform His duties. The soul which is able to realize this One and only One Ishwar achieves Him and enjoys unconditional ultimate bliss or Moksha.
[Ishwar means God in Hindi]
Yajurveda 40.1:
This entire world is embedded within and managed by the One and Only One Ishwar. Never dare do any injustice or desire riches through unjust means. Instead follow the righteous path and enjoy His bliss. After all He alone is source of all bliss!
Rigveda 10.48.1
Ishwar alone is omnipresent and manager of entire universe. He alone provides victory and eternal cause of world. All souls should look up only to Him in same manner as children look up to their Father. He alone provides for our sustenance and bliss.
Rigveda 10.48.5
Ishwar enlightens the entire world. He alone is undefeated and undying. He alone is the creator of the world. All souls should seek bliss through seeking knowledge and acting thereupon. They should never shun the friendship of Ishwar.
Rigveda 10.49.1
Ishwar alone provides true knowledge to truth seekers. He alone is promoter of knowledge and motivates virtuous people into noble actions to seek bliss. He alone is the creator and manager of the world. Hence never worship anyone else except one and only Ishwar.
Yajurveda 13.4
There is one and only One Creator and Maintainer of the entire world. He alone is sustaining the earth, sky and other heavenly bodies. He is Bliss Himself! He alone deserves to be worshiped by us.
Atharvaveda 13.4.16-21
He is neither two, nor three, nor four, nor five, nor six, nor seven, nor eight, nor nine, nor ten. He is, on contrary, One and Only One. There is no Ishwar except Him. All Devtas reside within Him and are controlled by him. So He alone should be worshiped, none else.
Atharvaveda 10.7.38
Ishwar alone is greatest and worth being worshiped. He is the source of all knowledge and activities.
Yajurveda 32.11
Ishwar resides at each point in universe. No space is devoid of Him. He is self-sustaining and does not need help of any agent, angel, prophet or incarnation to perform His duties. The soul which is able to realize this One and only One Ishwar achieves Him and enjoys unconditional ultimate bliss or Moksha.
[Ishwar means God in Hindi]