When Hashem told Avraham not to kill Yitzchak at the Akeidah, Avraham looked up and saw a ram which he sacrificed in place of Yitzchak. We are told that it wasn’t happenstance that Avraham found a ram; instead, according to a mishna in Pirkei Avot, this particular animal was one of the things that Hashem created at the very end of the sixth day of creation. Why did Hashem select a ram and not some little, docile creature? After all, we know that Avraham had to deal with this animal by himself (since he had left his two servants far away from the site of the akeidah, and Yitzchak was still bound on the mizbeach), and Avraham was not a young man (probably 137 years old). Since Hashem had all of this foreknowledge, wouldn’t it have been kinder for Him to create a small, weak animal to deposit in the thicket for Avraham to find?
Perhaps since Avraham was looking for an “olah tachat b’no” (a replacement for his son), he needed something that was most representative of Yitzchak. This required a strong, robust animal since Yitzchak is characterized by the middah of gevurah (strength). A meek animal, like a lamb or a goat, wouldn’t suffice for this purpose. (Note that there are no pick-up trucks or football teams named for these creatures.) The mighty ram was the perfect surrogate for Yitzchak because it personified his inner strength.
