Joseph Blenkinsopp discusses the ancestor cult among the Israelites during the First Temple era.
Joseph Blenkinsopp, “The Family in First Temple Israel,” in Families in Ancient Israel, ed. Leo G. Perdue, Joseph Blenkinsopp, John J. Collins, and Carol Meyers (The Family, Religion, and Culture; Louisville, Ky.: Westminster John Knox Press, 1997), 81
Ancestor Cult
Dead kinsmen, especially those long dead, joined the ranks of the shades (rěpā’îm) and in some obscure sense entered into the sphere of divinity, reflected in occasional references to dead ancestors as ‘ělohîm, “divinities.” In this respect Israelite beliefs differed little, if at all, from those of the entire area. We recall now, on seeing the ghost of Samuel, the witch of Endor explained, “I see divine beings [‘ělohîm] coming up from the underworld (1 Sam. 28:13; author’s translation). What kind of cult was offered to or on behalf of forebears is difficult to determine, since state orthodoxy proscribed rituals of this kind in the belief that they subtracted from the official Yahweh cult; which perhaps helps to explain the emphasis in temple hymnography on postmortem oblivion (e.g. Ps. 6:5; 88:4-6). We may find a clue in Absalom’s setting up his own monument since he had no son to invoke or keep in remembrance of is name (hazkîr šěmî, 2 Sam. 18:18). In Mesopotamia the invoking of the name (šuma zakāru) was an essential part of the funerary ritual (kispu), which included the offering of food and pouring of a water libation for the dead; and similar ceremonies are attested elsewhere in the Near East and Levant. With that frequency and on which occasions these rites were observed during the time of the kingdoms we do not know. Reference in Jeremiah 16:5-9 to the “house of morning” and the “house of feasting” (bêt marzēaḥ, bêt mišteh) in connection with funerary rites suggests a parallel with the marzēaḥ funerary meal attested at Ugarit and in many other centers down into the Greco-Roman period. This appears to have been initially a kind of wake at which the living celebrated the departed members of the clan while assuaging their sorrow, relieving the tensions of everyday life, and reinforcing the kinship bond with the help of strong drink. They no doubt thought of it as a religious experience, and perhaps that is all that matters.