As of 18 April, 2000, the 18th day of April of every year shall be set aside to "commemorate the memory of King David of Israel…"
King David's story is a tale of human mortality. He is not a divine figure; he is divinely inspired, but he remains both human and flawed, so that even people in the 21st century can relate to him.
He began life as a humble shepherd, a capable musician, and a poet. Called to the service of his King and Country, he killed Goliath, and became renowned in the reign of the first king of Israel, Saul. But Saul became jealous of his young protégé, and David had to flee the royal court, to live the life of an outlaw in the wilderness.
When King Saul and his son were killed in battle, the elders of Judah and Israel elected David King. And thus was born the legend of the Great King, who founded Jerusalem as the Eternal City of David, where he brought the holy Ark of the Covenant, marking a new covenant, the covenant between God and Israel as embodied by the living House of David.
To commemorate the memory of the Great King, the Day of Observance for King David was selected because it is the birthday of his direct, living descendant, who is a living link with the ancient King of Israel. On 18 April, 1959, Marc Eric Ely-Chaitlin of the House of David was born, and as the living representative of the ancient King, it was on his birthday that the Observance takes place. It seems only fitting that the Day of Observance should come on a day that represents the living continuity of David's legacy.