Is it permissible for an entire supplication to consist of prayers upon the Prophet (peace and blessings be upon him), and is it legislated to raise the hands while doing so?

The virtue of sending blessings upon the Prophet is immense, and the hadith of Ubayy ibn Ka'b, "Then your worries will be sufficient for you, and your sins will be forgiven," is authentic. The intention is not to abandon supplication altogether, but rather to dedicate a specific time or a particular supplication to sending blessings upon the Prophet, or to include it in every supplication. The word "salati" (my prayer/blessings) in the hadith means "my supplication." Sending blessings upon the Prophet is akin to remembrance and praise, so it is not sunnah to raise the hands during it, even though some scholars permit raising them by analogy with the general evidence for raising hands in supplication.