Final answer:
The indissoluble sacrament established by God mentioned in the question is Marriage. It is considered as one of the fundamental sacraments in Christian traditions, especially within Catholicism, representing a sacred, lifelong union between spouses.
Step-by-step explanation:
The sacrament which shares a bond established by God himself and is indissoluble by human authority is called Marriage. In the Christian context, particularly within Catholicism, Marriage is viewed as a sacred covenant between individuals that is divinely instituted. This sacrament is one of the key rites in the faith, alongside others like Baptism, Communion, Confirmation, and the Last Rites. Each of these sacraments serves a distinct spiritual purpose within the life of the believer, sanctifying different stages of life and spiritual development.
Marriage, for instance, is believed to be sanctified by God and is a public declaration of a lifelong commitment made between the spouses. The indissoluble nature of this sacrament signifies that the union cannot be broken by any earthly power, illustrating the profound importance placed on marital vows within the Church. The solemnization of Marriage as a sacrament also reflects the Christian ethos of love and fidelity mirroring the relationship between Christ and the Church.