When we examine the principles of solidarity and subsidiarity in the light of the Gospel, we realize that they are not simply “horizontal”: they both have an essentially vertical dimension. Jesus commands us to do unto others as we would have them do unto us (cf. Lk 6:31); to love our neighbour as ourselves (cf. Mat 22:35). These laws are inscribed by the Creator in man’s very nature (cf. Deus Caritas Est, 31). Jesus teaches that this love calls us to lay down our lives for the good of others (cf. Jn 15:12-13). In this sense, true solidarity - though it begins with an acknowledgment of the equal worth of the other - comes to fulfilment only when I willingly place my life at the service of the other (cf. Eph 6:21). Herein lies the “vertical” dimension of solidarity: I am moved to make myself less than the other so as to minister to his or her needs (cf. Jn 13:14-15), just as Jesus “humbled himself” so as to give men and women a share in his divine life with the Father and the Spirit (cf. Phil 2:8; Mat 23:12).
Similarly, subsidiarity - insofar as it encourages men and women to enter freely into life-giving relationships with those to whom they are most closely connected and upon whom they most immediately depend, and demands of higher authorities respect for these relationships - manifests a “vertical” dimension pointing towards the Creator of the social order (cf. Rom 12:16, 18). A society that honours the principle of subsidiarity liberates people from a sense of despondency and hopelessness, granting them the freedom to engage with one another in the spheres of commerce, politics and culture (cf. Quadragesimo Anno, 80). When those responsible for the public good attune themselves to the natural human desire for self-governance based on subsidiarity, they leave space for individual responsibility and initiative, but most importantly, they leave space for love (cf. Rom 13:8; Deus Caritas Est, 28), which always remains “the most excellent way” (cf. 1 Cor 12:31).