The allegory is first a story, and secondly a lesson. The lesson will not be taught unless there is a story to follow. Therefore, the allegory spends time on the efforts of the Lord of the vineyard and his servant. Some commentators have suggested that we are seeing Elohim the father and Jesus the son as the Lord of the vineyard and the servant respectively. That would be a modern perspective, but not one that would have informed Zenos’ or Jacob’s understanding.
As children of Israel, Zenos and Jacob believed in one God, who was Jehovah. Therefore, the Lord of the vineyard had to be Jehovah. As Jehovah is the celestial realm designation for the mortal realm’s Jesus, the Lord of the vineyard and servant would not be the same person. It is better to understand Jehovah as the Lord of the vineyard and perhaps a prophet as the servant.
The two come to the vineyard after waiting to see what the effect of the last effort produced. It had begun to work. The grafting in of the gentiles allowed the original covenant to be refreshed, and the results were “like unto the natural fruit.” That is, there is no difference in God’s eyes whether one was naturally of the house of Israel or adopted into it. The covenants nourish all who come to that source.