Genesis 44:15

New English Translation

¹⁵Joseph said to them, “What did you think you were doing?^[a] Don’t you know that a man like me can find out things like this by divination?”^[b]

Genesis 44:15 tn Heb “What is this deed you have done?” The demonstrative pronoun (“this”) adds emphasis to the question. A literal translation seems to contradict the following statement, in which Joseph affirms that he is able to divine such matters. Thus here the emotive force of the question has been reflected in the translation, “What did you think you were doing?”
Genesis 44:15 tn Heb “[is] fully able to divine,” meaning that he can find things out by divination. The infinitive absolute appears before the finite verb for emphasis, stressing his ability to do this.

New English Translation (NET)