Why did Hashem instruct them to build the Mizbe'ach on Har Eival (the mountain on which the K'lalos were said) and not on Har Gerizim?
Oznayim la'Torah #!: Because, knowing that the Shomronim were destined to switch Har Gerizim for Yerushalayim, He took the wind out of their sails by ordering the Mizbe'ach on Har Eival. Otherwise they would have strengthened their claim by arguing that Har Gerizim on which the B'rachos were given and which housed the Mizbe'ach, is indeed the chosen mountain.
Oznayim la'Torah: To soften the impact of the K'lalos for those who read out the K'lalos on Har Eival - in that the Korbanos that they brought on it would protect them..
Why does the Torah spell "ba'Sid" with a 'Siyn' instead of with a 'Samech'?
Oznayim la'Torah: Presumably, because it refers to the better-quality type of lime that was used for ornamentl purposes, as opposed to the regular type that was used for building, which is spelt with a 'Samech'. 1
Se also Oznayim la'Torah, citing the Alshich.
Why was it necessary to cover the writing with lime?
Oznayim la'Torah: a. Because it is forbidden to teach Nochrim Torah, and b. Because it is forbidden to translate the Torah into any language other than ancient Greek. 1 Consequently, even though here they were fufilling a Divine Command, Hashem instructed them to cover the letters - until the Nochrim came and uncovered them. 2
Where was Har Eival?