As per this resistance 5e spell you would touch one of your willing creatures. But once before end of this spell, then the target can roll a d4 and also add the number rolled to one saving throw of its choice. So it can roll a die before the saving throw or after the saving throw. Finally the spell will end.
Attributes Of DnD 5E Resistance
| Casting Time | 1 action |
| Classes | Cleric, Druid |
| Components | V S M |
| Concentration | Yes |
| Duration | Up to 1 minute |
| Level | 0 |
| Material | A miniature cloak |
| Name | Resistance |
| Range | Touch |
| School | Abjuration |
| Target | One willing creature |
I really like all the points you have made here.