Charles H. Spurgeon on Psalms 139:5

Thou hast beset me behind and before, etc. There is here an insensible transition from God's omniscience to his omnipresence, out of which the Scriptures represent it as arising. "Behind and before", i.e., on all sides. The idea of above and below is suggested by the last clause. "Beset", besiege, hem in, or closely surround. "Thy hand", or the palm of thy hand, as the Hebrew word strictly denotes. —Joseph Addison Alexander.