What is the rhetorical subtlety in the Almighty's saying: "And [mention] when Abraham was raising the foundations of the House" instead of "And when Abraham was raising the foundations of the House"?

Indeed, it is stated in Al-Razi's Tafsir that the reason for Allah's saying, "And [mention] when Abraham was raising the foundations of the House" (Surat Al-Baqarah, 2:127) and not "raising the foundations of the House" (بناء على "يرفع قواعد البيت" وليس "يرفع قواعد البيت") is that the ambiguity of "the foundations" (القواعد) followed by their clarification magnifies their significance.