The middle section of the eightfold path concerns sila (ethics): samma vaca (right speech), samma kammanta (right action), and samma avija (right livelihood).
Here are a medley of considerations:
Positioning the paths within the path
The eightfold path sets off from an acknowledgement of suffering. So too the paths of sila are means towards an eradication of suffering. 
The logic of the sila is simultaneously deeply personal – what are the factors of behaviour that tend to suffering – but also deeply concerned with harmony (via a complex chain of comprehension that reveals the obvious to be arbitrary and then to be intuitive once more).
This harmony extends past the self to affect society; it extends within the train of the self’s experience to affect the psychological and kammic entities; and it extends within the domain of mindfulness to affect contemplation.
Following on from the first two paths, the paths of sila act under consideration of right view and right intention. If one has a right view of the nature of experience (most obviously and succinctly relevant per the four noble truths) then all behaviours will be seen as either expressions of ignorance leading to suffering, or of wisdom leading to nibbana. If one has a right intention – to renunciation, harmlessness, and good will – then all behaviours will be seen as expressions aligning with those goals or moving away from them.
Comprehending right speech
Samma vaca manifests itself most obviously in the avoidance of unwholesome speech (especially as lies as hurtful statements), and in the approval of wholesome speech (especially as truth and helpful statements). In the texts this is expressed as a fourfold division: abstention from (1) false speech, (2) slanderous speech, (3) harsh speech, and (4) idle chatter.
The meaning of speech as wholesome or unwholesome derives from its expression of a defilement. Thus it is enlightening to perceive unwholesome speech as following from motivation, and the nature of motivation being one of the defilements. Examples include motivation of greed to gain, hate to hurt; delusion is less obvious but may be demonstrated by situations wherein one is carried away by a false possibility, as in an interesting exaggeration or a joke.
The significance for truth can be extended beyond its effects onto others. Speech exemplifies the process of illusion (qua concealment or distortion of truth), and so is a model for the way an individual relates to their own standard of truth. The mental state of being carried away by a lie is paralleled whether one is talking to another or to themselves.
Truthful speech provides, in the sphere of interpersonal communication, a parallel to wisdom in the sphere of private understanding. Devotion to truthful speech is a matter of taking our stand on reality rather than illusion, on the truth grasped by wisdom rather than the fantasies woven by desire. (Bikku Bodhi)
The significance of idle chatter (nb. the least obviously unwholesome of the categories) can be seen along these lines. Idle speech can be read as an extension of the internal dialogue that relates oneself to their reality. It may encourage defilements or weakening of the mind’s wisdom by its uncaring (or attenuating of priorities relating to the) relationship between its own values and any objective value. (I use “objective values” to mean something like right view, and at the very least, a standard that holds there to exist falsehoods).
It may be noted that idle chatter (and all forms of speech) may be matters of selective reception as much as selective expression. And in this regard, the role and value of popular media may be considered.
Mindfulness of avoidance and performance
The behaviours that develop sila may be predicated on habituation, and also on self-consideration. The latter may be established on a framework of standards – like those described by the texts for samma vaca, kammanta, and avija. To direct oneself towards these standards requires training particular capacities for varitta (avoidance) and caritta (performance).
The categories of the right behaviours may be used as descriptors and labels for recognizing and enhancing mindfulness of the behaviours that are so familiar and so often disregarded or mindlessly pursued without probation.
When I talk I know that speech is a behaviour that may be ethical. When I talk I know whether my speech is wholesome or unwholesome, which category, and by what root. In this way I may become familiar with the occurrences of speech, with their ethical nature, with their ethical category, and with their expression of a mula. In this way I may become familiar with the tendency towards expressions of the mula, and with right intention; in this way I may become familiar with my capacity for moving towards wisdom and away from ignorance by manifesting behaviours.
A metric for wholesomeness
In Buddhist ethics volitions may be wholesome or unwholesome, and these modalities may be measured. Two unwholesome actions that are superficially identical may differ in their ethical magnitude. This value may be simplified as the calculation of how hard or how easy the behaviour was to perform.
It is worse to kill something that is hard to kill than easy (e.g. because of its physical size). It is worse to kill something that is (more) intuitively sacred (e.g. because of its righteousness). It is worse to kill something with low benefit (i.e. the benefit to onself). It is worse to kill something with low temptation (i.e. of craving, e.g. without a heightened passion or in cold calculation).
These considerations describe ethics in terms of a bending or flowing of a will. The more a will must be coerced into action, the more potent the ethical salience of the action. The more a will is following its own mindless conditioning, the less potent the ethical action is relevant to the actor.
Nurturing wholesome kamma
By this means a mindfulness of behaviours’ ethics may be expanded to incorporate a sense for the nurturing of kamma (good or bad).
When I know how an action flows from past kamma – because of my consideration of difficulty, or significance, or reward, or craving – then I may know whether the stream of kamma is flowing blindly or whether the stream is being diverted and in which way and to what extent. In this way I may become familiar with behaviours as resulting from a kamma that includes my proclivities for behaviours and considerations, and I may become familiar with behaviours as modulating future kamma.
Mindfulness of good friends
Some of the textual advice for behaviours extend beyond the the easy to categorize three-fold speech, action, livelihood. For example in the Sigalovada Sutta, Buddha gives an array of practical and mundane, including on what to look for in a friend. There are 4 characteristics described that may be identified in false friends, and in good friends.
Aside from the benefit this offers to a technical analysis and comprehension of company, it also implies a criteria for what should be desirable, and hence prompts consideration of the role of others in our life. In addition to all this, by the very nature of its detailing characteristics, the Sutta may be used as a prompt for enhancing mindfulness of the positive and negative values inherent in all relationships – considering the other as a friend and considering oneself as a friend to the other.
Modes of foes in the guise of friends
They appropriate our possessions, including asking much and giving little, associating out of fear, or associating for advantage
They render lip service, including making friendly claims about the past, about the future, using empty words to gain favour, and claiming inability during opportunity to help us.
They flatter, including approving of our evil deeds, disapproving of our good deeds, praising us in our presence, or speaking ill of us in our absence.
They bring ruin, including by being companions in our heedless intoxication, or unseemly choices.
Modes of warm hearted friends
I can be a helpmate to my friend, including by guarding them when they are heedless, or by doubling supply during when commitments are needed.
I can be the same for my friend in happiness and in sorrow, including by sharing with them my secrets, and receiving theirs, or not forsaking during misfortune.
I can give good counsel to my friend, including encouraging their good, and informing them of what they don’t know.
I can be sympathetic to my friend, including by rejoicing with their prosperity, by restraining others from speaking ill of them, and by praising others who speak well of them.
Attending to friendship
By noticing the exchange of value in my relationships with others, I may notice the modes of behaviour that are wholesome and benefitial and those that are unwholesome and hurtful. by noticing the tendency of modes of behaviour to benefit or to hurt, I may become more mindful about the value of others as those I relate to.
When a person takes from me, or when I take from a person, I may be mindful of those that appropriate possessions. When a person claims they are my friend, or when I remind them I am their friend, I may be mindful of those that render lip service. When a person flatters me unreasonably, or I flatter them unreasonably, then I may be mindful of those that flatter. When a person shares unwholesome activities with me, I may be mindful of those that bring ruin to others. In this way I may not be hurt by others, and not hurt others; including those I hold to be my friends.
When a person gives me service, then I may be mindful of those that are helpmates, and I may intend to be a helpmate to others. When a person shares secrets, then I may be mindful of those that are a rock, and I may intend to be a rock to others. When a person gives me good counsel, then I may be mindful of those that are counsellors, and I may intend to be counsel to others. When a person shares and defends my happiness, then I may be mindful of those that are sympathetic, and I may intend to be sympathetic to others.
Sources:
- The way to end suffering by Bikkhu Bodhi
- Everyman’s Ethics: Four Discourses of the Buddha translations by Thera
