1 Peter 3:8

Finally, be ye all of one mind
Not that the apostle was about to conclude his epistle; but having finished his exhortations respecting the obedience of subjects to magistrates, and of servants to their masters, and the duties incumbent on husbands and wives, he proceeds to sum up what he had further to say, in general rules; which regarded all sorts of Christians, magistrates and subjects, masters and servants, husbands and wives, parents and children, old and young, rich and poor, of whatsoever state, age, sex, or condition; and so the Arabic version renders it, "the sum of the commandment is"; and the Ethiopic version, "the sum of all is this"; namely, what follows; "be ye all of one mind"; whatever difference there might be in their natural and civil relation and character; and which is to be understood not of the sameness of affection to one another, or of an humble and condescending spirit, disposition, and carriage to each other, for these are expressed in some following exhortations; but of sameness of judgment with respect to the doctrines and ordinances of the Gospel, in which saints should be perfectly joined together in the same mind, and in the same judgment; for as the church is but one body, of which Christ is the head, there should be but one mind in it; even as there is but one Spirit of God, who convinces, enlightens, and leads into truth; and but one heart and way, given to fear the Lord; and there is but one hope of our calling, or to which we are called; and one way to it, and therefore ought to agree in everything respecting the way, the truth, and the life; though in things which do not, should bear with one another; and there is but one Lord, who gives the same laws and ordinances to one as to another, and which are to be kept alike by all; and there is but one faith, one doctrine of faith, which is uniform and all of a piece, and but one rule and standard of faith, the sacred Scriptures, and but one baptism, to be administered in the same way, and upon the same sort of subjects, and in the same name of the Father, Son, and Spirit; and but one God and Father of all; all belong to the same family, and therefore should preserve a unity of spirit and mind, and speak the same things; which is necessary to carry on the worship of God, honourably and regularly, to the glorifying of him, and for the peace, comfort, and safety of the churches of Christ:

having compassion one of another;
or sympathizing with each other, both in prosperity and adversity, whether in temporal or spiritual things; rejoicing with them that rejoice in Christ, make their boast of him, and have communion with him, and who are also blessed with health of body, and a competency of the good things of this life; and weeping with them that weep for the loss of goods, relations, &c. and being in bonds and afflictions; or because of sin, the absence of Christ, and the temptations of Satan; and being concerned also for such who are fallen into immorality, or error, and heresy; endeavouring to restore them out of the one or the other, in a spirit of meekness and tenderness: to all which they should be engaged by the example of Christ, the sympathizing high priest; by the consideration of the divine compassion to them, both in a providential way, and in a way of grace; and on account of their union and relation to each other, as members of the same body:

love as brethren;
not in a natural and civil, but in a spiritual relation, being children of God, and brethren of Christ, and in a Gospel church state; and whose love to each other ought to be universal, fervent, without dissimulation, and as Christ has loved them; and which should show itself in praying for each other, in bearing one another's burdens, in forgiving each other, in admonishing in love, and building up one another on their most holy faith, and communicating to each other both in temporals and spirituals: and of a very excellent nature is it; it is the bond of perfectness, and evidence of regeneration; the glory and ornament of a profession, and without which it is nothing; and what renders the communion of the saints with each other pleasant and profitable, comfortable to themselves, and honourable in the eyes of others; and to which they should be induced from the consideration of the love of God and Christ unto them, and from their relation to each other, as brethren:

be pitiful;
to those that are in distress; put on bowels of mercy, and relieve and succour them, distributing cheerfully to their necessities:

be courteous;
gentle and affable, carrying it friendly to one another, seeking those things which may be most agreeable to each other, shunning all moroseness, stiffness, and incivility. The Vulgate Latin version renders it by two words, "modest, humble": not proud, haughty, and overbearing, but condescending to each other, and to men of low estates; and so the Syriac version renders it, "kind and meek".