jnatva putrasya tat karma
desan nihsarayam asa
sutam tyakta-vidhim rusa
jnatva—knowing; putrasya—of his son; tat—that; karma—action; guruna—by the spiritual master (Vasistha); abhihitam—informed; nrpah—the King (Iksvaku); desat—from the country; nihsarayam asa—drove away; sutam—his son; tyakta-vidhim—because he violated the regulative principles; rusa—out of anger.
When King Iksvaku, thus informed by Vasistha, understood what his son Vikuksi had done, he was extremely angry. Thus he ordered Vikuksi to leave the country because Vikuksi had violated the regulative principles.
Link to this page: https://prabhupadabooks.com/sb/9/6/9