1) Ch. 12, v. 4: "Va'yeilech Avrom kaasher DI'BER eilov Hashem" And Avrom went just as Hashem spoke to him In verse 1 we find, "VaYOMER Hashem el Avrom." Why the change from "amiroh" to "dibur?"
2) Ch. 14, v. 14: "Shmonoh ossor ushlosh mei'os" Three-hundred and eighteen Rashi (gemara N'dorim 32a) says that this refers to Eliezer, Avrohom's slave, whose name has the numerical value of 318. This is a most difficult explanation of our verse, as the verse expresses itself in the plural form, "chanichOV, y'lidEI." This is especially puzzling in understanding Rashi, who has set out to explain the Torah in a straightforward "pshuto shel mikra" manner (Breishis 3:8).
3) Ch. 14, v. 22,23: "Harimosi yodi, Im michut v'ad sroch naal" I have raised my hand, If from a thread to a shoelace Why was it necessary for Avrom to raise his hand and utter an oath that he would take none of the spoils of war? If he indeed takes nothing it is obvious that he would be keeping his word.
4) Ch. 15, v. 15: "V'atoh tovo el avoshecho b'sholom" And you will come to your forefathers in peace The M.R. 38:12 derives from these words that Terach, Avrohom's father, repented. How is this conclusive? Perhaps Terach would not repent, but the merits of Avrohom would protect Terach in his judgment in the world-to-come, as per the gemara Sanhedrin 104a, "A son's good deeds are a merit for his father."
5) Ch. 16, v. 2: "Ulai ibo'neh mi'menoh" Perhaps I will build through her How would Soroh build a family through Hogor's having children?