Both the narrow gate and the wide gate are assumed to provide the entrance to God’s kingdom. Two ways are offered to people. The wide gate includes all religions of works and self-righteousness, but it leads to hell, not heaven.
Commentary from the MacArthur study Bible, notes for Matthew 7:13,14.
Enter through the narrow gate.
For the gate is wide and road is broad
that leads to destruction,
and there are many
who go through it.
“He must not be able to suspect that he is now, however slowly, heading right away from the sun on a line which will carry him into the cold and dark of utmost space.” The Screwtape Letters by C. S. Lewis