c.1500, from hand (n.) + writing, translating Latin manuscriptum. Hand in the sense of "handwriting, style of writing" is from late 14c.
An ordinary note in his [Horace Greeley's] handwriting is said to have been used for a long time as a railroad pass, then as a servant's recommendation, and finally taken to a drug-store as a doctor's prescription. ["Frank Leslie's Magazine," August 1884]
(Col. 2:14). The "blotting out the handwriting" is the removal by the grace of the gospel of the condemnation of the law which we had broken.