Psalms 16:5 - Matthew Poole's English Annotations on the Holy Bible

Of mine inheritance, or, of my division, i.e. of that inheritance which God hath mercifully divided or distributed to me, and which I by his grace have chosen for myself. I envy not the vast riches and glory of idolaters, but do heartily rejoice in God as my portion, and desire no better nor no other felicity. God, who hath suffered other nations to walk in their own idolatrous ways, hath granted this favour to me, to know and worship him, the only true God. And as other nations have chosen and do adhere to their false gods, so have I chosen God, and will cleave to him. And of my cup; the same thing repeated in other words. The portion of my cup, is the portion which is put into my cup, as the ancient manner was in feasts, where each had his portion of meat and of wine allotted to him. See Psalms 11:6. The cup oft denotes a man's portion or condition, as Matthew 2:22; Matthew 20:39. Thou maintainest my lot, i.e. my inheritance divided to me by lot, as the custom then was, Joshua 18:11 Judges 1:3: q.d. As thou hast given me an excellent lot, having planted me among thine own people, and in that place which thou hast chosen for thy dwelling and worship, so, I doubt not, thou wilt uphold and preserve me there, in spite of all the malicious designs of mine enemies that seek to drive me hence.