“Sarah’s.” Added to the text for clarity. Her demand caused Abraham great distress. He loved Ishamel, who was 14 when Isaac was born (Gen. 16:16; 21:5), and now, at Isaac’s weaning, may have been as old as 19.
“word.” The Hebrew word is dabar (#01697), the common word for “word,” but also, like the Greek logos, had a wide range of meanings, including “thing,” “matter.” Thus the translation might well read, “This matter,” or “This thing.”
“grievous.” The Hebrew word, raa (#07489), is more commonly “bad,” but has a wide range of meanings, thus the English translation varies quite a bit. To Abraham, Sarah’s demand was “bad,” “wrong,” “hurtful,” “distressing,” “difficult,” “displeasing,” etc. All these accurately express what Abraham felt and was going through in facing casting out his son, whom he would never see again. In the next verse we see that our gracious God spoke to Abraham and helped him deal with his emotions and the situation.