Then the servant took ten of his master’s camels and set out, taking with him all the bounty of his master; and he made his way to Aram-naharaim, to the city of Nahor. He made the camels kneel down by the well outside the city, at evening time, the time when women come out to draw water. And he said, “O ETERNAL, God of my master Abraham, grant me good fortune this day, and deal graciously with my master Abraham: Here I stand by the spring as the daughters of the townsmen come out to draw water; let the maiden to whom I say, ‘Please, lower your jar that I may drink,’ and who replies, ‘Drink, and I will also water your camels’—let her be the one whom You have decreed for Your servant Isaac. Thereby shall I know that You have dealt graciously with my master.” He had scarcely finished speaking, when Rebekah, who was born to Betuel, the son of Milcah the wife of Abraham’s brother Nachor, came out with her jar on her shoulder.
Rabbi Shmuel bar Nachmani said that Rabbi Yonatan said: Three people entreated God in an unreasonable manner. To two of them God responded reasonably, and to one God responded unreasonably. And they are: Eliezer, servant of Abraham; Saul, son of Kish; and Jephthah the Gileadite. Eliezer, servant of Abraham, as it is written: “That the maiden to whom I shall say: Please let down your pitcher” (Genesis 24:14). Eliezer entreated God unreasonably, as his request allowed for the possibility that she might even be lame or even blind, and yet he had promised to take her to Isaac. Nevertheless, God responded to him reasonably and Rebecca happened to come to him. Saul, son of Kish, he made an offer when Goliath the Philistine challenged the Israelites, as it is written: “And it shall be that the man who kills him, the king will enrich him with great riches, and will give him his daughter” (I Samuel 17:25). The man who killed Goliath might even have been a slave or a mamzer. Nevertheless, God responded to him reasonably and David happened to come to him. Yiftach the Gileadite, as it is written: “Then it shall be that whatever comes forth from the doors of my house to meet me when I return in peace…it shall be to the Lord and I will bring it up for a burnt-offering” (Judges 11:31). This might even have been an impure, non-kosher animal. In this instance, God responded to him unreasonably, and his daughter happened to come to him.
But doesn’t Rav say that any divination that is not like the divination of Eliezer, the servant of Abraham, when he went to seek a bride for Isaac (see Genesis 24:14), or like the divination of Jonathan, son of Saul, who sought an omen as to whether he and his arms bearer would defeat the Philistines (see I Samuel 14:8–12), is not divination?...
Rav would check based on the ferry. And Shmuel would check by opening a scroll. Rabbi Yochanan would check by asking a child to recite the verse he was learning.
"It's difficult to make predictions, especially about the future."