The morsel which thou hast eaten shalt thou vomit up, and lose thy sweet words.
The morsel (which) thou hast eaten shalt thou vomit up. You will yet have reason to wish you could give him back his food, when you discover that it was so grudgingly given. Or, imperatively, With all speed return him the hospitality which he gave, and for the future abstain from it in disgust.
And lose thy sweet words. Thou shalt lose the good that thou thoughtest to have done by "thy sweet words" interchanged with him at his table. Thou shalt repent of having wasted thy good words, like seed sown on a barren soil.