To this point, Jacob has been speaking of the heavenly Jehovah and the plan as set in motion in the heavens. He will now shift to discuss how that plan will become realized on earth. The transition from one theme to another is his declaration of Jehovah’s omniscience. That covers Jehovah knowing that the overall plan would work as well as how it would be implemented.
The implementation required that Jehovah leave his celestial realm and become mortal. He will be sufficiently mortal that “he suffereth the pains of all men.” This echoes Jacob’s statement that mortals must bear the crosses of the world. Jehovah, as a mortal, will suffer the pains that all men suffer. Perhaps here Jacob is alluding to Isaiah 50:6 (2 Nephi 7:6): “I gave my back to the smiters, and my cheeks to them that plucked off the hair: I hid not my face from shame and spitting.”
Jehovah will suffer as man suffers so that the resurrection might be for all, including the ability to repent and stand before Jehovah at the final day of judgment.