"against/ The deep damnation of his taking-off;/And pity, like a naked-born babe..."(1.7.19-21) and what type of literacy device is it?
Your quote needs a little more at the beginning and end for it to make sense to you. Macbeth starts by talking about Duncan's virtues then switches to talking about the murder of Duncan.
Will plead ... against
The deep damnation of his taking-off;
And pity, like a naked new-born babe,
Striding the blast, .../.../
Shall blow the horrid deed in every eye, (I.vii)
Shakespeare is using personification of pity here in Macbeth's Act I soliloquy. In this case, pity is being personified as "a naked newborn babe,/Striding the blast, or heaven's cherubim, horsed/Upon the sightless couriers of the air." In other words, this babe (Pity) will send forth such a lamentable cry that "Shall blow the horrid deed in every eye," telling the whole world that Macbeth murdered King Duncan.
Before that, Macbeth argues with himself by personifying virtue, saying that Duncan's virtues would plead like "trumpet-tongued" angels against the abomination of killing him. This part of his soliloquy is Macbeth's musing about whether or not he should follow through with killing the king.