Macbeth:"it is too full o' the milk of human kindness

In context, Lady Macbeth is referring to her husband when she says the line, Yet doe I feare thy Nature, It is too full o’ th’ Milke of humane kindnesse." Lady Macbeth is referencing her husband's goodness, and in turn, questioning his ability to do the deed... to kill King Duncan. The "milke of humane kindnesse" is something she sees as a flaw in her husband.... she is questioning his manliness.... proclaiming him to be weak.