Psalms 121:5 - Matthew Poole's English Annotations on the Holy Bible

Thy shade; both to refresh thee and keep thee from the burning heat of the sun, as it is expressed in the next verse, and to protect thee by his power from all thine enemies; for which reason God is oft called a shadow in Scripture. Upon thy right hand; partly to uphold thy right hand, which is the chief instrument of action; and partly to defend thee in that place where thine enemies oppose thee; of which on Psalms 109:6. And compare Psalms 16:8, Psalms 109:31.