Bialik’s Hebrew poetry and editing contributed to the development of modern Hebrew, as well as to the creation of the Israeli identity. During a key part of his life, he lived and worked in Odessa in a Jewish intellectual community that was a precursor of modern secular Jewish thought.
I'm not a big reader of poetry, so I won't repeat a lot of stuff about his poems. Just note that "In the City of Slaughter" about a pogrom in Kishinev in 1903 is a powerful and influential work. The poem expresses Bialik's first-hand indignation and horror at the destruction of a small Jewish community, to which he traveled to see the effects. Sadly, the most chilling fact about the poem that resonates today is that the death toll was 47 -- needless to say, the 20th century taught us all that racists could kill a much larger number than that.