28:12 a ladder … angels of God were ascending and descending. A graphic portrayal of the heavenly Lord’s personal involvement in the affairs of earth, and here especially as they related to divine covenant promises in Jacob’s life (vv. 13–15). This dream was to encourage the lonely traveler. God’s own appointed angelic messengers ensured the carrying out of His will and plans. More than likely, the angels traversed a stairway rather than a ladder.
MacArthur Study Bible
28:12 As he rests overnight, Jacob has a dream, which centers on a ladder set up on the earth, and the top of it reached to heaven. The Hebrew term translated “ladder” could possibly denote a stairway (see ESV footnote) similar to those found on ancient ziggurats (see illustration). What matters most is not the precise shape of this structure but its purpose; it provides a bridge between heaven and earth, revealing that God is still committed to making the earth his dwelling place (see Introduction: History of Salvation Summary). Jesus identifies himself as the ladder linking earth and heaven (John 1:51). While human beings want to ascend to heaven (as reflected in the Tower of Babel story, Genesis 11), God is interested in making the earth his temple-city.
ESV Study Bible
28:12 a ladder. Probably a vast stone ramp with steps. The phrase “top of it reached to heaven” recalls the description of the tower of Babel (11:4). Jacob may have seen a ziggurat. See notes 11:1–9 and 11:5.
earth … heaven … ascending and descending. Jacob’s dream of a meeting place between heaven and earth points forward to Jesus Christ, the God-Man who reunites heaven and earth (John 1:51 and note). Through Christ, the only “mediator between God and men” (1 Tim. 2:5), we have access to the Father (Eph. 2:18).
Reformation Study Bible