Who gives covenant promises and spiritual life in the story of the prodigal son?
In the story, the younger son realizes his need and returns to the Father, who is identified as the Giver of the covenant promises and the Giver of spiritual life. The son sees there is only one place to go for sustenance, so he goes back to Him.
Les explains that the younger son, like the one little lamb caught in the thicket, realizes his need and sees there is only one place he can go for sustenance—back to the Father. He must return to the Giver of those covenant promises, to the Giver of spiritual life, and so he does. This fits the broader point that Jesus’ parables were showing the Jew their state and their need of Him.