God compared Abraham's descendants to the stars and the sand. Just as people cannot count the huge number of stars or the grains of sand, so there would be so many of Abraham's descendants that people would not be able to count them. Alternate translation: "beyond what you can count" (See: [[rc://en/ta/man/translate/figs-simile]])
Here "gate" represents the whole city. To "possess the gate of their enemies" means destroying their enemies. Alternate translation: "will completely triumph over their enemies" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-metonymy]])