There is this passage in 语类, where the question of 天地之心 is discussed:
所以明道云:‘天地之常,以其心普万物而无心;圣人之常,以其情顺万事而无情。’说得最好。”问:“普万物,莫是以心周遍而无私否?”曰:“天地以此心普及万物,人得之遂为人之心,物得之遂为物之心,草木禽兽接著遂为草木禽兽之心,只是一个天地之心尔。
I find the following sentence in this passage problematic:
普万物,莫是以心周遍而无私否
How to understand this 莫 ? Does it relate to 万物 or to 天地之心?
My intuitive understanding of this is that it points to the fact that there is nothing left of the Heart/Mind to be personal Heart/Mind of Heaven and Earth (because it is all everywhere). But it is more a guess than a genuine understanding.