It is neither their flesh nor their blood that reaches Allah; it is your piety that reaches HIM." (Surah Al-Hajj 22:37)
"There is nothing dearer to Allah during the days of Qurbani that the sacrificing of Animals. The sacrified animals shall come on the Day of Judgement with its horns,hair and hooves (to be weighed). The sacrifice is accepted by Allah before the blood reaches the ground. Therefore sacrifice with an open and happy heart." (Tirmizi, Inb Majah)
"Qurbani is the way of our fore father Ibrahim. There is reward for every hair." (Ibne Majah)
Qurbani is obligatory on each Muslim (male or female) who hold a Nisab i.e minimal level of wealth. It is highly virtuous for one on whom Qurbani is not obligatory to offer sacrifice for the Pleasure of Allah. He will be eligible for all the reward mentioned in the Ahadeeth.
"Whoever has the capacity to sacrifice and does not do so, should not come to the place where the Eid prayer is offered." (Ibne Majah)
If somebody out of his/her ignorance and negligence did not offer ‘Qurbani’, he should then give the price of the ‘Qurbani’ as ‘Sadaqah’. This does not mean that Sadaqah is an alternative.