jnatva putrasya tat karma
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.