You have that wrong too. The elect is so great an amount that they can not be numbered (Gen 32:12). God is talking to Jacob, who he changed his name to be called Israel, (Gen 32:28), saying I will surly do you good and make thy seed as the sand of the sea, which cannot be numbered for multitude. The strait gate in Matt 5 is not talking about leading to eternal life, but to the abundant life that those of his elect have that have been revealed the truths of Jesus's doctrine. The wide gate are also the elect of God who have not been revealed the truth because they are going about to establish their own righteousness by their works. The people going in both gates are God's elect and will all go to heaven because Christ died for them.