Well you can make that correlation but it is not supported by sutta, as far as I know. There were certainly a number of monastics whose behaviour was not great even when the Buddha was still teaching. Are there instances of the Buddha telling someone not to go forth due to being not advanced enough?
Yes, it is not too well articulated, but still the evidences are there in the texts. The very idea of gradual approach actually speaks for itself in this case. No need to introduce it if there was/is no such correlation. As for the instances... well, I'll go into details then, especially that ryanM
also asked. This won't be short, though
So, how did that happen, that in all serious monasteries you are not allowed to ordain as soon as you like - while, as you notice, Buddha allowed that. Why is that?
Here is my answer. As we know from suttas, Buddha didn't want to teach at first, however, he surveyed the world and saw that there are many, who "can see Dhamma". That means, many spiritually developed people. And yes - as soon as he started, he almost immediately "made" more more than 1000 arahants. As it seems (and Commy confirms that) all those people were there because of their excellent past kamma and paramis (and even direct past-life connections with the Buddha and best disciples personally). That is, their minds were strong and clean, while defilements, clingings, delusions - very weak. Almost no dust in the eyes (c). They were ready, they were waiting, and he came to pick them up -) There were also others - "more difficult cases", as they say.. ))). This was no one minute work for him. It required much more time and patience to grow them up into arahants. But he still succeeded, because he was an omniscient Buddha, he knew how to do it and that it is possible to do. With the most difficult, but highly potent people, he dealt himself directly. The best example here is such unthinkable and abnormal case like Angulimala story. But there were also others - who could make it to arahantship in their very life without Buddha's personal interference. They could
make it (relatively easily) but only in the right circumstances - like monkhood. Buddha knew that, saw that, and understood that he just can't handle it all alone - handle all those personal instructions and so on. So he established Sangha and opened its gates for everyone. Ehi bhikkhu!
He knew many would fail, I think, he even knew, some would fall in hell because of their misdeeds.... but still he wanted those many potent people from different regions to reach arahantship or non-returning as soon as possible - so they could stay in the world and keep Dhamma pure and clean, helping many more people around and in the future.
Short answer: he could make restrictions, this would certainly make Sangha more "clean", but at the same time that would slow down the increment of arahants. Actually on a certain moment of history he did start to introduce "restrictions" to keep the balance, but it didn't work too well anyway (not because Buddha miscalculated, but because those "spiritually potent people" simply came to an end). In MN 65 there is a VERY interesting conversation: "Venerable sir, what is the cause, what is the reason, why there were previously fewer training rules and more bhikkhus became established in final knowledge? What is the cause, what is the reason, why there are now more training rules and fewer bhikkhus become established in final knowledge?” - That is how it is, Bhaddli. When beings are deteriorating and the true Dhamma is disappearing, then there are more training rules and fewer bhikkhus become established in final knowledge".
This passage is very important, because it shows that fact of tangible decrease of "potent people" already during Buddha's lifetime. Beings are deteriorating
---> this is what he said. Less and less arahants. All those who were ready to start their practice with the highest stages of the path and fulfil them in no time, thus reaching final goal - they all made it and less and less such people remained to be found.
Now, if we extrapolate that (deplorable) trend in the future, and up to the present time... well... no words are needed here - everything is on the blackboard ))).
From here one can understand why all these monasteries - unlike Buddha - introduced "sandboxes" for modern sincere spiritual seekers allowing them to receive bhukkhu status only after years of supervision. The absense of this "defence" showed one thing: Sangha is being filled to the brim with spiritually weak people - while (ideally) it should be filled with exemplary ones, those, who could (like in good old times) pick up jhana practice and become an arahant in 7 days!
. By the way, in Korean Zen monasteries it is even stricter: one needs to spend not less than 10 years before he'll be granted the full ordination. Again, the answer is short: "people are coming, but they are not ready". Gone are the days when people put on ochre robes and became enlightened in 7 days or at least 7 years. Sandboxes, though not too efficient, at least block the most unprepared spiritual seekers, making it easier for the community of those who are at least somehow prepared
. It is not that senior monks and abbots are elitists or smth - no. It is just life dictates these rules.