In the post Rebirth – Connection to Suffering in the First Noble Truth, the rarity of human bhava is discussed. It is also mentioned in several suttas in Sanyutta Nikaya.
But as far as my understanding, this rare occurrence of human bhava applies to the asathpurisa or putthajana – those who don’t have any faith in Buddha, Dhamma, Sangha and those who are regularly engaged in dasa akusala (basically average humans).
But for those who have faith in the Triple Gem and those who are fulfilling the paramitas, human bhava is NOT rare for them. Of course they are not free from the apayas, but even if they are reborn in woeful planes, they come back to the sugati realms more often due to the power of their merits/paramitas.
Suppose there is a bag full of 100 balls – 99 black balls and 1 white ball.
If a person is to take out a ball from this bag, what do you think which ball would have higher probability? Black or White ? Of course the black balls have 99% probability and the white ball has just 1% probability.
Here black balls represent the papa kammas and white balls represent the punna kammas of a person. And the bag represents the set of kamma bija for a given sentient being. This is the case of a putthajana.
Of course in reality there are uncountable kamma bija in the nama loka for a given sentient being, and other complex factors also come into play at the cuti-patisandhi. Hence this is just a crude analogy.
And for those who are fulfilling the paramitas, the situation is just the reverse! More white balls and less black balls.
So if one is willingly and honestly striving/fulfilling the paramitas, nature would give him more and more chances/opportunities to do the same! (i.e., one would be reborn more often in the human and deva realms)
The law of Paticca Samuppada !!!
My point is that a person fulfilling the paramitas or aspiring (honestly) to fulfill the paramitas SHOULD NOT BE DISCOURAGED.
Most Ven. Waharaka Thero also mentioned in one of his sermons that a Buddhist even if he/she born in apayas would come back quickly to the human realm without spending much time in apayas!
Here is the link to the sermon (the relevant part starts at 16:29 minutes)
Theruvan Saranai !!!