Making a king's descendant become king in his place is spoken of as placing him on that king's throne. AT "I will cause one of your descendants to rule Israel in your place" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here "your sons" represents the descendants of David that would become king. AT: "your descendants" (See: [[rc://en/ta/man/translate/figs-synecdoche]])