This morning something dawned on me while reading Genesis 2. Maybe this is the first time this has stood out to me. I don’t know. But Genesis 2.15 says that YHWH Elohim (the LORD God) took the earthling (ha–adam), placed him the garden of Eden, and did so with the responsibility to ‘work and keep‘ or ‘serve and guard‘ it (laabedah ulesamerah/לְעָבְדָ֖הּ וּלְשָׁמְרָֽהּ). (On a side note, in 2.5 there’s also a comment about the earthling serving/working the earth/ground which provides an interesting juxtaposition with Genesis 1.26-28’s ‘dominion’ ecology.) Later in 3.24, once the earthling is driven from the garden, cherubim are placed at the entry with a flaming sword in order ‘to guard the way to the Tree of Life’ (לִשְׁמֹ֕ר אֶת־דֶּ֖רֶךְ עֵ֥ץ הַֽחַיִּֽים), which is done in order to prevent the humans from reentering the garden to consume from the tree (3.22-23).
Now, I know the semantic range of forms of shamar/שָׁמַר allow for the humans to ‘keep’ (as in ‘tend to’) the garden while the cherubim are to ‘guard’ (like ‘protect’) but it seems to me that this narrative is moving from the humans being the ones who guard/protect/keep to the ones from whom the garden must be guarded/protected/kept.