So, this seems to be the fundamental difference between Theravaden and Mahayana practices, the activation(maturity) of the bodhicitta vow. Our individual practice of meditation could be indistinguishable between the two lineages, but if one has this seed it will mature and produce a Buddha fruit.
The concept of the vow is also present in Theravada. When Shakyamuni was an ascetic named Sumedha in a previous life, the Buddha Dipamkara was turning the wheel. He was ripe for Arhathood in that very life should he engage in the insight meditative practices taught to Dipamkara's Arhat disciples. However, he wanted to become a Buddha so that he can lead others into liberation, so he made a vow before Dipamkara and he was given the vyakarana that he will indeed become a Buddha in the distant future.
From what I can tell, the difference in the bodhisattva practice between Theravada and Mahayana is that in Theravada, the insight practices between the Sravaka Arhat and the Bodhisattva in his last life are the same, and the only difference is that the Bodhisattva spends eons to develop his paramis, and during this time, he should not engage in the insight practices lest he slips into the stream. In Mahayana, besides the cultivation of the roots of merits, there are also myriad insight practices and non-dual meditations that are taught in the Mahayana sutras.
In this respect, I feel that the Theravada method is lacking in something. Even in Theravada, the Buddha's wisdom and insight are supreme, and none of his Arhat disciples come close. So how can the Buddha attain such unsurpassed bodhi if the insight practices that leads to his full enlightenment are the same as the insight practices of his Arhat disciples? Perhaps they operate on the premise that during the long career of the Bodhisattva, he will naturally come across other teachings that are not explicitly taught in the Agamas.
if it is actually of any real importance to verbally say this vow or if it is more something that one would be inclined towards by simply following the path. It just seems a bit ritualistic for my tastes, but I suppose any one of us could have already taken this vow before.
If you do feel that you like to attain the fruit of a Buddha, then you can take it in your heart. To me, the ritual forms are not essential.
I would also like to thank you for sharing your vast accumulation of knowledge with me, and for your patience. I'm learning a new language here, and it will take some time to absorbe all the information provided. Maybe a few more lifetimes.
You are most welcome. I really do not possess any vast store of knowledge - only sharing with whatever Iittle I have learned. There are many here who are much more learned and cultivated than I am.
Please do feel free and continue to ask any questions.
If you believe certain words, you believe their hidden arguments. When you believe something is right or wrong, true of false, you believe the assumptions in the words which express the arguments. Such assumptions are often full of holes, but remain most precious to the convinced.
- The Open-Ended Proof from The Panoplia Prophetica