Almalexia's Blessing is a Restoration spell which temporarily increases the value of Luckand can be acquired in The Elder Scrolls III: Tribunal. The attribute return to its original value when the spell ends. that can be acquired in The Elder Scrolls III: Tribunal.
This spell is not available for purchase and cannot be obtained during regular gameplay. Although not intended for use by the Nerevarine, it can be acquired on the PC by using the console command:
Player -> AddSpell "almalexia's blessing"