In the ancient world, people sought to know the will of the gods through a variety of means. For example, a person might consult the dead by offering blood libations to underworld deities. People would also examine animal organs for divine messages, cast lots, and mix water and oil in a cup. All of these were methods of divination.

If you read Psalm 16 from the perspective of an ancient diviner, the vocabulary starts to look familiar. A cup: people poured water and oil into one and read the patterns, which is why Joseph’s silver cup could be used for divination (Genesis 44:5). Lots: cast to reveal a hidden choice, as the sailors did with Jonah. Kidneys and liver: cut from a sacrificed animal and searched for signs, as the king of Babylon did at the crossroads (Ezekiel 21:21).

All four appear in the psalm. But none are used for divination.

“The LORD is my chosen portion and my cup; you hold my lot” (v. 5). “In the night my kidneys instruct me” (v. 7, where most English Bibles say “heart”). “My heart rejoices, and my liver is glad” (v. 9, a likely reading of the Hebrew).

The cup is the LORD himself. The lot is in his hand. And the kidneys and liver belong to the psalmist, not to an animal on an altar. No one is reading them. They are being taught, and they are glad.

Read more on psalms.scriptura.org → Psalm 16 Poetic Features