Although they are not necessarily for the Paladin to wield the Light (nor is that a claim anyone has made?), the blessings are what sets them apart from your typical Cleric - which as defined in Rise of the Lich King and Of Blood and Honour are actual Warrior-Priests.
Paladin is above that, being completely remade, scrubbed clean, and filled back up with the Light. The terms “born anew” are literally used to describe the process.
Turning to face the entire assembly, the Archbishop said, “Brothers—you who have gathered here to bear witness—raise your hands and let the Light illuminate this man.” Each of the Clerics and knights raised their right hands and pointed toward Tirion. To Tirion’s amazement, their hands began to glow with a soft, golden radiance. He supposed that, in the excitement of the moment, his eyes were playing tricks on him. Yet, as he watched in wonder, the sunlight that poured in from above began to move slowly across the floor.
As if in response to the assembly’s command, the light came to rest upon Tirion himself. Partially blinded by the intense radiance, Tirion felt his body warmed and energized by its holy power. Every fiber of his being was ignited by divine fire. He could sense life-giving energies flowing through his limbs, energies enough to heal any wound or cure any disease. He mused that these energies were enough to burn even the souls of the accursed denizens of the shadow. Despite himself, he shuddered involuntarily.
Ablaze with hope and joy, Tirion knelt down and took hold of the mighty hammer—the symbol of his holy appointment and station. With joyous tears streaming down his face, he raised his head and looked toward the Archbishop, who smiled warmly back at him.
“Arise, Tirion Fordring—Paladin defender of Lordaeron. Welcome to the Order of the Silver Hand.”
And then the sunlight streaming in through windows in the ceiling slowly began to move toward the prince standing alone in shining armor, and Arthas exhaled in relief. This had to be what Uther had spoken of. The feeling of unworthiness that Uther assured him all paladins felt simply seemed to drag out the moment. The words Uther had spoken came back to him:* No one feels he deserves it… its grace, pure and simple… but the Light loves us anyway.*
Now it shone down on him, in him, through him, and he was forced to shut his eyes against the almost blinding radiance. It warmed at first, then seared, and he winced slightly. He felt—scoured. Emptied, scrubbed clean, then filled again, and he felt the Light swell inside him and then fade away to a tolerable level. He blinked and reached for the hammer, the symbol of the order. As his hand closed about the haft, he looked up at Archbishop Faol, whose benign smile widened.
“Arise, Arthas Menethil, paladin defender of Lordaeron. Welcome to the Order of the Silver Hand.”
Arthas couldn’t help it. He grinned as he grasped the enormous hammer, so large that for a brief moment he thought he wouldn’t be able to lift it, and swung it upward with a whoop. The Light, he realized, made the hammer seem to weigh less in his hands. At his exultant cry, the cathedral suddenly began to ring with the sound of answering cheers and applause.
Every fibre of their body is infused with the Light’s divine fire, making them able to perform superhuman feats like lifting those massive hammers of theirs that no ordinary human could lift, and they’re born anew.
[Citation required]