The line: "Yet do I fear thy nature; It is too full o' the milk of human kindness to catch the nearest way" is in which play by William Shakespeare?

In William Shakespeare's play "Macbeth", the line: "Yet do I fear thy nature; It is too full o' the milk of human kindness to catch the nearest way" is used by Lady Macbeth in Act I, Scene V (14-17). Lady Macbeth uses this quote immediately after reading a letter she has received from her husband. In his letter, Macbeth informs his wife that witches have prophesied that he will be king.

Macbeth is telling Lady Macbeth the news so she can share in the joy that the prophesy has brought him. Macbeth tells his wife, "This have I thought good to deliver thee, my dearest partner of greatness, that thou might'st not lose the dues of rejoicing, by being ignorant of what greatness is promised thee. Lay it to thy heart, and farewell."

In the play, it is revealed that Macbeth is not a brutal character. In fact, Lady Macbeth worries that her husband might be too kind and unable to kill the current king. Accordingly, unlike him, she may only be somewhat pleased with the news that he may become king. She can see hidden problems that he may have to face if he should become the country's ruler. Does or will he have the temperament and skill set needed in a king? Lady Macbeth will discover the answer. She is not too kind.

It may be very true that during a time of humanitarian giving and generosity, she (Lady Macbeth) could remain uncaring, heartless, callous, and hard-nosed.