Charles H. Spurgeon on Psalms 122:8

For my brethren and companions' sakes, I will now say, Peace be within thee. It is to the advantage of all Israel that there should be peace in Jerusalem. It is for the good of every Christian, yea, of every man, that there should be peace and prosperity in the church. Here our humanity and our common philanthropy assist our religious prayer. By a flourishing church our children, our neighbours, our fellow countrymen are likely to be blest. Moreover, we cannot but pray for a cause with which our dearest relatives and choicest friends are associated: if they labour for it, we must and will pray for it. Here peace is mentioned for the third time. Are not these frequent threes some hint of the Trinity? It would be hard to believe that the triple form of so many parts of the Old Testament is merely accidental. At least, the repetition of the desire displays the writer's high valuation of the blessing mentioned; he would not again and again have invoked peace had he not perceived its extreme desirableness.