The Sinaitic teachings were not of an ephemeral nature, even in regard to their form. Being engraven on tables of stone, they could be easily remembered by successive generations. During a long period these inscribed slabs remained in the custody of the Israelites, and were called "the Tables of the Testimony," or "the Tables of the Law." Being placed in an ark, which became a rallying centre, round which Moses used to assemble the elders of the families, these tables served as a sign of the Sinaitic Covenant. They formed a link between God and the people who had formerly been trodden under foot, and who were now bidden to own no other Lord save the One from whom the Law had gone forth. It was for this reason that the ark, as the repository of the tables, was designated "the Ark of the Covenant." The ethical truths of Sinai became henceforth the basis for a new system of morality, and for the national constitution of the Israelites. These truths were further developed in special laws which had a practical bearing upon the public and private affairs of the people. Slave-holders and slaves were no longer to be found amongst the Israelites. The selling of Israelites as slaves, and perpetual servitude of an Israelite became unlawful. A man who forfeited his liberty was liable to be held in service during six years, but in the seventh year he regained his freedom. Wilful murder and disrespect to parents were punishable with death. The sanctuary could give no protection to criminals condemned to die. The murder of a non-Israelitish slave involved condign punishment. A gentile slave ill-treated by his master recovered his liberty. A man committing an offence on the virtue of a maiden was bound to make her his wife, and to pay a fine to the father of the injured woman. Equitable and humane treatment of the widow and the orphan was enforced; a similar provision was ordained for the benefit of strangers who had joined one of the tribes. The Israelites, in fact, were bidden remember their former sojourn in a foreign land, and to refrain from inflicting upon strangers the inhuman treatment which they themselves had formerly endured.