The Buddha describes how having good or bad friends affects higher behavior, proper training, the perfection of ethical behavior, and the abandoning of lust for sense pleasures, lust for forms and lust for the formless.
Read the Sutta
Index to available translations: AN 6.67
Hare finds this sutta confusing. It doesn't help that he so constructs the first concept, 'abhisamacarikam dhammam,' (forms of higher-behavior) as 'the Dhamma-fore-course' thus making the series linear rather than circular.
It is not that the first step is completed before the next step, but that as each step is partially developed it provides a foundation for advancement into the partial development of the next step.
Aspiration and testing higher forms of behavior provides insight into the advantages of higher forms of behavior and the disadvantages of lower forms of behavior.
Insight into higher forms of behavior provides motivation for further development of higher forms of behavior and the next step of taking up the recommended forms of training.
Taking up the training results in insights into the advantages of training and the benefits of further developing higher forms of behavior and the advantages of further training and the taking on of the task of fully developing ethical behavior.
Testing forms of ethical behavior leads to insights into the advantages of letting go of lust for sense-pleasures, forms, and the formless.
With each step forward there is the recognition that a more fully developed foundation is an advantage, round and round.
The end result is the fulfillment of each stage resulting in the fulfillment of the next stage, thusly:
The fulfilment of higher behavior fulfills the training,
the fulfillment of the training fulfills, ethical behavior,
the fulfillment of ethical behavior fulfills the abandoning of lust for sense pleasures,
lust for forms,
and lust for the formless.
As this is fulfilled, that is fulfilled, not when this is fulfilled go on to the next step and fullfill that, etc.
Essentially this is saying that higher forms of behavior = training = ethical behavior = abandoning lust for sense pleasures, lust for forms and lust for the formless.
I could probably figure out a fourth way of saying this if I worked at it.
"This being, that becomes;
on the cessation of this, the cessation of that."