Look at it is plain no one can open it form out side.
Often we pray, pray to the Lord for favors and graces. But often we forget that the Lord has the power to grand what you need and he will. Some other times we pray we will not be in a disposition to receive the grace that is asked of the Lord.
It is almost like calling for dinner and not opening the door. Jesus knocks at the door of everyone heart. He can’t be in by himself until you open it. We need to say honesty to the Lord. Lord do take charge of me, do come into my life in my thoughts, words and deeds.
Do you feel it is true that we often pray without having true faith?