7. He that overcometh--another aspect of the believer's life: a conflict with sin, Satan, and the world is needed. Thirsting for salvation is the first beginning of, and continues for ever (in the sense of an appetite and relish for divine joys) a characteristic of the believer. In a different sense, the believer "shall never thirst."
      inherit all things--A, B, Vulgate, and CYPRIAN read, "these things," namely, the blessings described in this whole passage. With "all things," compare 1Co 3:21-23.
      I will be his God--Greek, "I will be to him a God," that is, all that is implied of blessing in the name "God."
      he shall be my son--"He" is emphatic: He in particular and in a peculiar sense, above others: Greek, "shall be to me a son," in fullest realization of the promise made in type to Solomon, son of David, and antitypically to the divine Son of David.

JFB.