Society, however, cannot subsist among those who are at all times ready to hurt and injure one another. The moment that injury begins, the moment that mutual resentment and animosity take place, all the bands of it are broke asunder, and the different members of which it consisted are, as it were, dissipated and scattered abroad by the violence and opposition of their discordant affections. If there is any society among robbers and murderers, they must at least, according to the trite observation, abstain from robbing and murdering one another. Beneficence, therefore, is less essential to the existence of society than justice. Society may subsist, though not in the most comfortable state, without beneficence; but the prevalence of injustice must utterly destroy it. (TMS II.ii.3.3)
What chiefly enrages us against the man who injures or insults us, is the little account which he seems to make of us, the unreasonable preference which he gives to himself above us, and that absurd self-love, by which he seems to imagine, that other people may be sacrificed at any time, to his conveniency or his humour. The glaring impropriety of this conduct, the gross insolence and injustice which it seems to involve in it, often shock and exasperate us more than all the mischief which we have suffered. To bring him back to a more just sense of what is due to other people, to make him sensible of what he owes us, and of the wrong that he has done to us, is frequently the principal end proposed in our revenge, which is always imperfect when it cannot accomplish this.(TMS II.iii.1.5)
No society can surely be flourishing and happy, of which the far greater part of the members are poor and miserable. It is but equity, besides, that they who feed, cloath and lodge the whole body of the people, should have such a share of the produce of their own labour as to be themselves tolerably well fed, cloathed and lodged. (WN I.viii.36).
An educated populace can, to a degree, regulate political actors who may wish to take advantage of inequalities for their own benefit. The uneducated are easily misled and suffer for it. The more the ‘inferior ranks of people’ are instructed, Smith says,
the less liable they are to the delusions of enthusiasm and superstition, which among ignorant nations, frequently occasion the most dreadful disorder. An instructed and intelligent people besides are always more decent and orderly than an ignorant and stupid one. They feel themselves, each individually, more respectable, and more likely to obtain the respect of their lawful superiors, and they are therefore more disposed to respect those superiors. They are more disposed to examine, and more capable of seeing through, the interested complaints of faction and sedition, and they are, upon that account, less apt to be misled into any wanton or unnecessary opposition to the measures of government. In free countries, where the safety of government depends very much upon the favourable judgment which the people may form of its conduct, it must surely be of the highest importance that they should not be disposed to judge rashly or capriciously concerning it.(WN V.i.f.61)
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Smith does have a lot to say about Social Justice, but it is ignored by those who's actions would not be justified by it.
If Capitalism is to survive, it must work hand-in-hand with social justice. To ignore that part of the equation, invites dissent and revolution that will reduced us to the equality of poverty.