Possible meanings are 1) "song people sang while going up to Jerusalem for a celebration" or 2) "song people sang while going up the steps into the temple" or 3) "song whose words are like steps." See how you translated this in [Psalms 120:1](../120/001.md)
This is a hypothetical statement that describes a result that did not happen, because Yahweh was actually on their side. AT: "Yahweh was on our side ... so they were not able to swallow us up alive" (See: [[rc://en/ta/man/translate/figs-hypo]])