At first glance, the wording seems ambiguous about the moment of the saving throw:
The target must succeed on a Wisdom saving throw or follow the command on his next turn.
In theory, one could read that "in his next turn" applies only to the effect or both to the effect and to the saving throw. However, with a little work, we can show that this moment can not Be interpreted as the trigger for a release of salvation. Thus the time must be applied only to the effect, do not The salvation shot.
First, if we observe other spells that require targets to perform saving throws in their own turns, we notice a pattern: the spell is always very specific about when the saving throw occurs. For example, the text of grease He says:
A creature that enters the area or ends its turn there must also be successful in a Dexterity saving throw or in a prone fall.
… any creature that starts its turn there must be successful in a Force save roll or receive 6d6 of direct damage and be dragged 10 feet to the center.
When a creature enters the area of the spell for the first time in a turn or begins its turn there … it must make a Constitution saving throw. Take 2d10 of radiant damage in a failed save, or half damage in a successful one.
After moving in this way, you can make another Wisdom saving throw to try to finish the effect.
The point of all these examples is that any spell that requires a saving throw at any time other than immediately at the beginning of the duration of the spell says so specifically, and in addition, always provides a specific trigger for that saving throw. In particular, if a creature has to make a save roll on its own turn, the spell always specifies exactly when During his turn, salvation occurs: either at the beginning of his turn, at the end of his turn, or when a certain event occurs, such as moving towards an affected area. The other pattern to keep in mind is that whenever a specific trigger is given for a save roll, the information is always presented in the same order: first the trigger, then the save roll and finally the effect.
In contrast, the text of I send It does not follow this pattern. Specify the saving throw first, then the effect and then the time. And compared to the previous examples, the moment of "on your next turn" is not specific enough. It does not give a precise trigger for when the saving throw occurs. (Of course, the obvious time would be the beginning of the target's turn, but it does not say that). On the other hand, this time make It makes perfect sense when applied to the effect: it says that the target spends its entire turn following the command. Therefore, we must conclude that the time given applies to the effect, not to the saving throw. Since the time for the saving throw is not specified, we return to the "default": the saving throw occurs when the spell is cast.
Based on the previous examples, we can imagine what the spell might tell if the intention was for the objective to roll salvation in its own turn:
At the beginning of the next turn of the target, he must succeed in a Wisdom saving throw or follow the command on that turn.