Earnestness is the path of immorality
Earnestness is the path of immortality (Nirvana),
thoughtlessness the path of death.
Those who are in earnest do not die,
those who are thoughtless are as if dead already.
Dhammapada chapter II, verse 21
The way Buddha paid attention to concentration through right behaviour says the fact that attendant had been taught nothing but right manners: right posture, walking, sitting, talking, clothes wearing, eating, appealing etiquette to seniors and juniors, monks and laypeople and etc. for the first 108 days. It is look like "external" things. But are they external in relation to Dharma practice?
An body assemblage is a token of mind assemblage. Exactly because such an attention is paid to posture assemblage while contemplation. However practice is not limited with the formal sitting meditation time. Actually real practice begins at a moment, when you are leaving contemplation and returning to a real world, which is full of countless defilements and distractions. We must save steadfast peace and concentration in this world or all our contemplative achievements will disperse like a fog under wind.
A fit and neat body, assemblage and restraint are the shield that defend our spirit from three samsara poisons: greed, hatred and delusion. You must hold your body so that your posture and movements become majestic and perfect regardless of standing or sitting you are. Your movements must be like you are taking part in regardless of in front of Buddha itself. Then your spirit will acquire proper concentration and strength itself without which you can't even dream about Enlightment Fruits.
Keep always in your mind, that if you took refuge in Buddha, Dhamma and Sangha, you became Enlightment warriors with evil Mara's forces. That's why any your weakness, lack of discipline and not-assemblage will be used the Enemy against you and your spiritual brothers and sisters. Have you ever seen an army without strict discipline?! Even not too experienced, but disciplined army won enormous hordes of enemies, which were reigned by anarchy and lack of discipline. Remember about it forever and keep your internal spiritual army in strictness and discipline. Watching the lack of discipline around you, don't justify your own weakness, like 'person in a crowd'. On the contrary, improve yourself in aspiration for achieving perfectness in behaviour. Be like spirit of warrior.
One of qualities, which a human tells from a dull animal, is a aspiration for perfectness and enjoying that state. When you are improving in your behaviour, when you are enjoying your body assemblage, perfectness of movements, accuracy and clearance of your words, your imperturbable and self-disciplined character, you will rise up above animal life of "a person of crowd" and become immortal god. It was said by Fully Enlightened One: "Earnestness is the path of immortality, thoughtlessness the path of death. Those who are in earnest do not die, those who are thoughtless are as if dead already."
There no stop and place for rest and laziness in a self-perfection. The Path is already the Aim, the Air is already the Path. That's why a river, which stops flowing, become a musty bog. That's why you must never stop at what has been accomplished, don't repose on your laurels, but sharpen your behaviour again and again whenever it is possible. Keep in your mind that demon of ordinariness is always on a guard to plunge you into delusion defilement. That's why you must be especially watchful in the most neutral situations, when nobody sees you and you do the most prosaic deeds. A true discipline is revealed not in war time, when your life is in danger, but in relaxing peace time. Thus first of all you must be especially careful while you are in comfortable place with pleasant companion, friends and relatives. Because just in that time you take risks of unapparent losing all you have applied so hard.
Generally speaking remember always and everywhere: you are sons and daughters of Enlightened One's family, holy Dharma army warriors, brothers and sisters of holy brotherhood of Sangha. That's why always be aware, that you and only you are responsible for greatness and glory of the Three Jewels.