Albert Barnes Commentary Psalms 16:6

"The lines are fallen unto me in pleasant places; Yea, I have a goodly heritage." — Psalms 16:6 (ASV)

The lines - The word used here refers to the "lines" employed in measuring and dividing land (Amos 7:17; 2 Samuel 8:2). Therefore, the word comes to denote a portion of land that is "measured out" (or "surveyed") to anyone—his possession or property; and thus, the word also refers to one's condition in life. The meaning here is that in carrying out such a survey, "his" inheritance had been established in a pleasant and desirable part of the land.

Are fallen to me - This refers to the allocation of the different parts of the land by lot. The idea is that the land was surveyed into distinct portions, and then the part that fell to anyone was determined by lot. This was actually the case in distributing the land of Canaan (Numbers 26:55; Numbers 33:54; Numbers 36:2; Joshua 15-19).

In pleasant places - In a pleasant or desirable part of the land.

Indeed, I have a goodly heritage - A good, a desirable inheritance. The meaning is that he regarded it as a desirable heritage to live where the true God was known, and where he enjoyed God's favor and friendship.