Why does the Torah use the double expression "Veyada'ata ha'Yom Vahashevoso el Levavecha"?
Knowledge with the mind is insufficient. If one does not take the lesson to heart, the heart (alias the Yeitzer ha'Ra) will override one's knowledge. 1
As the Gemarra says in Sanhedrin, 106b 'Rachmana Liba Ba'i'
What are the connotations of "Ein Od"?