Ge 15:2
15:2 And Abram said, {a} Lord GOD, what wilt thou give me,
     seeing I go childless, and the steward of my house [is]
     this Eliezer of Damascus?

     (a) His fear was not only lest he should not have children,
         but lest the promise of the blessed seed should not be
         accomplished in him.

Ge 15:8
15:8 And he said, Lord GOD, {b} whereby shall I know that I
     shall inherit it?

     (b) This is a particular motion of God's Spirit, which is
         not lawful for all to follow, in asking signs: but was
         permitted for some by a peculiar motion, as to Gideon
         and Ezekiel.

Ge 15:10
15:10 And he took unto him all these, and {c} divided them in
      the midst, and laid each piece one against another: but
      the birds divided he not.

      (c) This was the old custom in making covenants,
          Jer 39:18, to which God added these conditions,
          that Abram's posterity would be as torn in pieces, but
          after they would be rejoined: also that it would be
          assaulted, but yet delivered.

Ge 15:13
15:13 And he said unto Abram, Know of a surety that thy seed
      shall be a stranger in a land [that is] not theirs, and
      shall serve them; and they shall afflict them {d} four
      hundred years;

      (d) Counting from the birth of Isaac to their departure of
          Egypt: Which declares that God will allow his to be
          afflicted in this world.

Ge 15:16
15:16 But in the fourth generation they shall come hither again:
      for the {e} iniquity of the Amorites [is] not yet full.

      (e) Though God tolerates the wicked for a time, yet his
          vengeance falls on them when the measure of their
          wickedness is full.