Does the threat for abandoning Friday prayer three times include the two sermons or just the prayer itself? And what is the ruling on one who misses three Friday prayers out of negligence and then repents?

The hadith (definition) that states, "Whoever abandons three Jumu'ahs out of negligence, Allah will seal his heart," is authentic. The intended meaning is abandoning the Jumu'ah prayer, i.e., not attending it and suffice with praying Dhuhr individually or in congregation. It is forbidden for a Muslim to delay after the call to Jumu'ah until after the sermon ends; rather, he must hasten to it immediately. And whoever falls into this sin or any other sin, and then repents with sincere repentance, his repentance will be accepted and his sins will be forgiven.