The Shu”t Mishneh Halachos (13:79) asks on the minhag to eat on the night of Rosh Hashanah an apple dipped in honey, and about the minhag to dip the challah into both honey and salt, and not just salt like all year round. He is bothered that this seems to contradict the Gemara in Horiyas and Kerisus which just mentions about eating gourd, fenugreek, leeks, beets, and dates, and makes no mention of dipping an apple in honey, or about dipping challah into honey?
He answers: There is a bris kerusah [everlasting covenant] with salt that it will never get spoilt. Not only that, but any food salted with salt is preserved and the salt saves the food from becoming bad, this is the nature and power of salt. However, the nature of salt is that it helps save food from becoming bad, however, for something which is bad already, salt doesn’t have the strength to fix it and make it good again. However, when it comes to honey, we find that Chazal say that even if it has mixed into it feet from bees, which is a tomei sheretz [non-kosher creature] it is permissible to eat. Rabbeinu Yonah (cited in the Rosh, Berachos 43) explains: Because the feet of the bee that is mixed into the honey changes and becomes heter [permissible]. Therefore, it is permissible to consume honey even though it has bee’s feet mixed inside.
According to this, honey is better than salt, in that it has the ability to change a prohibited item into a permissible item, whereas salt can’t change something, but it can preserve something and keep it as it is.
On Rosh Hashanah we do teshuvah and ask Hashem to forgive us for our sins. Moreover, we hope to do teshuvah out of love, which has the ability to turn our aveiros into mitzvos (as is clear from Yoma 86b).
