[Stoottnoiciek]

Although metta & non-ill will seem to be the same, in reality can be subtlely different, which is why Buddha included "abandoning ill-will" rather than "developing metta" in his 2nd path factor.

for example, stock phrases for the path include the following:

Now, there is the case where a Tathāgata appears in the world...He teaches the Dhamma...He [the person discussed above], hearing the Dhamma, gains conviction in the Tathāgata and reflects: 'Household life is confining, a dusty path. What if I, having shaved off my hair & beard and putting on the ochre robe, were to go forth from the household life into homelessness?'

When he has thus gone forth, endowed with the monks' training & livelihood, then — abandoning the taking of life — he abstains from the taking of life. He dwells with his rod laid down, his knife laid down, scrupulous, merciful, compassionate for the welfare of all living beings.

Abandoning the taking of what is not given, he abstains from taking what is not given. He takes only what is given, accepts only what is given, lives not by stealth but by means of a self that has become pure. This, too, is part of his virtue.

Abandoning uncelibacy, he lives a celibate life, aloof, refraining from the sexual act that is the villager's way.

Abandoning false speech, he abstains from false speech. He speaks the truth, holds to the truth, is firm, reliable, no deceiver of the world.

Abandoning divisive speech he abstains from divisive speech. What he has heard here he does not tell there to break those people apart from these people here. What he has heard there he does not tell here to break these people apart from those people there. Thus reconciling those who have broken apart or cementing those who are united, he loves concord, delights in concord, enjoys concord, speaks things that create concord.

Abandoning abusive speech, he abstains from abusive speech. He speaks words that are soothing to the ear, that are affectionate, that go to the heart, that are polite, appealing and pleasing to people at large.

Abandoning idle chatter, he abstains from idle chatter. He speaks in season, speaks what is factual, what is in accordance with the goal, the Dhamma, and the Vinaya. He speaks words worth treasuring, seasonable, reasonable, circumscribed, connected with the goal.

He abstains from damaging seed & plant life.

He eats only once a day, refraining from the evening meal and from food at the wrong time of day.

He abstains from dancing, singing, instrumental music, and from watching shows.

He abstains from wearing garlands and from beautifying himself with scents & cosmetics.

He abstains from high and luxurious beds & seats.

He abstains from accepting gold & money.

He abstains from accepting uncooked grain... raw meat... women & girls... male & female slaves... goats & sheep... fowl & pigs... elephants, cattle, steeds, & mares... fields & property.

He abstains from running messages... from buying & selling... from dealing with false scales, false metals, & false measures... from bribery, deception, & fraud.

He abstains from mutilating, executing, imprisoning, highway robbery, plunder, and violence.

Abandoning covetousness with regard to the world, he dwells with an awareness devoid of covetousness. He cleanses his mind of covetousness. Abandoning ill will & anger, he dwells with an awareness devoid of ill will, sympathetic with the welfare of all living beings. He cleanses his mind of ill will & anger. Abandoning sloth & drowsiness, he dwells with an awareness devoid of sloth & drowsiness, mindful, alert, percipient of light. He cleanses his mind of sloth & drowsiness. Abandoning restlessness & anxiety, he dwells undisturbed, his mind inwardly stilled. He cleanses his mind of restlessness & anxiety. Abandoning uncertainty, he dwells having crossed over uncertainty, with no perplexity with regard to skillful mental qualities. He cleanses his mind of uncertainty.

Having abandoned these five hindrances — imperfections of awareness that weaken discernment — then, quite secluded from sensuality, secluded from unskillful qualities, he enters and remains in the first jhāna....

MN 38 the manner & extent to which non-cruelty & non-ill-will are practised above is not the same as in other suttas when the Brahma Vihara are practised at the completion of the path (as Vajrayana-like social values), where the Brahma Vihara are radiated in all directions.

As Acharya Buddhaghosa skillfully pointed out in his Visuddhimagga, the Brahma Vihara have 'near enemies' and 'far enemies'. The near enemies of the Brahma Vihara are worldly emotions such as affection, sorrow, rejoicing & indifference. In short, most of these emotions are based in filial love (pema; piya) rather than pure metta. The near enemies are based in self views.

Personally, I am yet to read a sutta where Buddha taught practising Brahma-Vihara for directly entering jhana. For example, SN 46.54 is a teaching in response to the Brahma Vihara practised by other sects, who did not accompany the Brahma Vihara with the factors of enlightenment.

Imo, for most, practising Brahma-Vihara exclusively may not lead to the abandoning of 'self-views', which is the prequisite for path entry. For most, practising Brahma-Vihara exclusively may not lead to the abandoning of the perception of 'beings'. Thus, the short-coming of Brahma-Vihara, for the non-stream-enterer, is it can keep the mind stuck in putthujjanaism.

Thus, cultivating Brahma-Vihara is not necessarily the same as abandonment. Thus, Mahayana includes Vajrayana at the end rather than at the beginning. Vajrayana teaches if emptiness is not realised then practising Vajrayana (i.e., the beautiful qualities of a deity) will result in delusion; in believing: "I am a deity".

Cultivating Brahma-Vihara is similar to 'living' where as abandonment is similar to 'dying'.

Kind regards