There are two ways of looking at Macbeth's state of mind in Act 1 Scene 7. Firstly, there is the concept of good and evil in terms of the two religions influencing Shakesperean society. The Catholic church had an emphasis on 'sin' either mortal or venial. In this context, Macbeth is fast reaching 'the point of no return' towards deliberate (mortal) sin - to commit an act of murder that is not even manslaughter or self-defence, but cold-blooded murder. There is an element of this coldness in his speech as his mindset hardens into determined evil doing.
The question is, is he rational at this point? Or is he mentally ill? If it is the latter (the second way of looking at it) then his culpability might be in question in the sense of whether he is responsible for his actions. If he is ill, then his state of mind might be that of the paranoid schizophrenic,psychotic or mildly delusional. His 'disocciative behaviour' towards others close to him point me in this direction - but the debate rages between experts, even today!
At this point in Shakespeare's "Macbeth," there is still conscience and reason in Macbeth. For, as he contemplates the assassination of Duncan, Macbeth realizes that there is no other reason than his ambition that "can leap over anything, even itself"(V,vii,27) for killing a good king. In addition, Macbeth senses that the evil deed of killing Duncan will come back upon him as he says that we are always punished here because we teach others how to murder (ll. 10-12)
Obviously, Macbeth has much inner turmoil in committing murder against a virtuous Duncan, "humble in his duty," and fears its repercussion. But, in his conflict, he always feels the pull of "vaulting ambition."
At the end of the scene, he is determined. He says, "I am settled and bend up / Each corporal agent to this terrible feat."
He knows he must put on an act for the King and thanes. He must act like "the serpent but be the flower under't." He says, "False face must hide what the false heart doth know."
He is convinced by Lady Macbeth's persuasive tactics in which she challenges his manhood. She calls him "green and pale," "afeard," and a "coward." Finally, the ultimate insult: she says he's like "the poor cat i' th' adage." In other words, a feminine creature who doesn't want to get her feet wet by dipping them into water to catch a fish. His manhood is reeling after this.
He responds, "Prithee, peace! I dare do all that may become a man; who dare do more is none." So, he's angry with his wife for using all the "wimp" rhetoric, and so he's resolved to murder.
In Act-I, Scene-VII the reference to "vaulting image" may refer to a horse leaping a fence too eagerly and falling on the other side. It is picture of a rider trying to vault into the saddle but ending up on the floor on the other side. Macbeth's thoughts have led him to a state of deep doubt about his own ability. But Lady Macbeth focuses on the ability to translate desire into action, for which Macbeth was initially reluctant. Now, she offers him a defination of manliness which is in keeping with his identity as a warrior. ("when you durst do it, then you were a man;/ And to be more than what you were, you would"). Macbeth makes the complimentary address to his wife thus :-"Bring forth men children only! For thy undaunted mettle should compose/ Nothing but males". The tender "babe" at breast from Lady Macbeth's own earlier image is turned here into "men children" who represent not tenderness but hardness and ruthlessness, a course Macbeth has now settled on.
In the world of Macbeth, manliness means the ability to kill. In fact, he reflects the assigned cultural values to the sexes that boy children are given to guns and girls dolls to play with. The male values which Macbeth admires are a parody of themselves.