reward
勑 centers on giving a reward, often in an official or formal context.
勑 combines 來 (come) and 力 (strength/power), likely suggesting the idea of bestowing a reward that comes with authority. The exact historical development is uncertain.
The left side 來 means 'come', and the right side 力 means 'power'. Imagine a powerful figure summoning someone to come and receive a reward.
For ライ, picture a line of people coming to receive a reward: line -> ライ, and each person steps forward to be rewarded.