The physical gates in this world fortify a property, allowing you to go in and out, and secure it to prevent access.  In the spiritual, there are gates as well.  

“Enter by the narrow gate; for wide is the gate and broad is the way that leads to destruction, and there are many who go in by it. Because narrow is the gate and difficult is the way which leads to life, and there are few who find it.”  Mathew 7:13-14

The Gate of Hell (broad or crooked gate), which is open to all who want to go in, and the Righteous Gate (straight or narrow gate) require those who want access to meet certain requirements.  

“Then one said to Him, “Lord, are there few who are saved?”

And He said to them,  “Strive to enter through the narrow gate, for many, I say to you, will seek to enter and will not be able. When once the Master of the house has risen up and shut the door, and you begin to stand outside and knock at the door, saying, ‘Lord, Lord, open for us,’ and He will answer and say to you, ‘I do not know you, where you are from,’” Luke 13:23-25

The key to the gate is your relationship with Jesus.  Do you know Him?  Seek to know Him today.