Student wrote:
“Can anybody share any document which proves that Mahāyāna is a later branch?”
To your question regarding Mahāyāna. In my opinion, I think the proof of it being a later branch is self-evident. One just needs to read the sutras. One red flag after another. Full of one contradiction and inconsistency after another. I think one could possibly write a book listing the contradictions/inconsistencies.
The sutras from Mahāyāna are in Sanskrit. The suttas from the Tipitaka are in Pali. The fact that the “sutras(not suttas)” are in Sanskrit and not in Pali alone, is a red flag. The Buddha did not give his discourses in Sanskrit. It was in Maghadhi. As Lal wrote in one of the posts: “Pāli is a version of Maghadhi suitable for writing down oral discourses in summary form suitable for transmission.”
From Preservation of the Buddha Dhamma :
“That is when the Buddha admonished them that Sanskrit was a language with musical overtones developed by the high-minded Brahmins and thus it was not possible to convey the true meanings of Maghadhi (Pali) words in Sanskrit; see, Chulavagga 5.33.”
From Chulavagga 5.33 :
“You are not, O Bhikkhus, to put the word of the Buddhas into (Sanskrit) verse. Whosoever does so, shall be guilty of a dukkata. I allow you, O Bhikkhus, to learn the word of the Buddhas each in his own dialect.'”
To get more clarity on Mahāyāna, I think you will find the following post in particular, to be beneficial. If you have not read it already, I highly recommend it:
The Saddharma Pundarika Sutra (Lotus Sutra) – A Focused Analysis
Here’s one of the best highlights from that post, major clear as day/obvious contradiction/inconsistency:
“This sutrā starts off by the Buddha saying that even though he had taught that there were three paths to nibbāna but now he is admitting that there is only one; when Ven. Ananda asked why, he says that he did not think people were “ready” for this higher doctrine. Thus instead of there being three vehicles (or paths) one can take, there is only one which is the great vehicle or the Mahāyāna (“mahā” is great and “yāna” is vehicle). And this is the path that he himself took by striving for aeons as a Bodhisattva to become a Buddha.
Continuing with this sutrā, now he (the Buddha) was advising everyone to become a Bodhisattava and to attain the Buddhahood. Then he assures all those Arahants present there, including Ven. Sariputta, that they themselves will become Buddhas. This is a complete lack of understanding of the concept of an Arahant (even though the sutta itself says that those Arahants had removed all defilements). An Arahant is not going to be reborn and thus there is no way for an Arahant to become a Buddha.”