Sforno on Numbers 32:17/ספורנו על במדבר ל״ב:י״ז

1עד אשר אם הביאונום “as long as we have not brought them, etc.” The construction is similar to Proverbs 8,26 עד לא עשה ארץ וחוצות, “while G’d had not yet made earth nor its attributes.” We also find something similar in Genesis 24,19 עד אם כלו, “until they have finished.”