One of the major themes in Beowulf is the relationship between a king and his thanes/warriors. Scyld is Hrothgar's ancestor - his great-grandfather. He is described as one who became great and commanded loyalty to those around him. The opening concludes with "That was a good king." As such, his funeral is carried out with great reverence.
When Scyld dies, he is given an honorable funeral as he was a good king. His thanes carry his body to the sea. They put him in a ship; the author describes him as "ring-giver" showing his generosity during his life. They fill the ship with treasure and weapons. This is befitting of a good king but it is also symbolic because Scyld was poor at the beginning of his life. This gesture of filling the ship with treasure reflects his honor as a king and his journey from being destitute to becoming successful. They put a golden standard high over Scyld's head, presumably atop the mast shining like a star/sun. Then the ship is pushed into the open water and the tide takes it away, its final destination unknown (perhaps symbolic of the mystery of the afterlife).
Men cannot truthfully say who received that cargo, neither counsellors in the hall nor warriors under the skies.