Matthew 6:7
But when ye pray, use not vain repetitions, as the heathens do, for they think they shall be heard for their speaking much:
Matthew 23:13
But wo unto you scribes and pharisees, hypocrites, who shut up the kingdom of heaven against men: for ye neither go in yourselves, nor suffer those that are entering to go in.
Luke 13:25-28
When the master of the house shall have risen up and shut the door, and ye begin to stand without and knock at the door saying, Lord, Lord, open unto us; and He shall answer and say to you, I know you not, whence ye are:
1 Timothy 2:8
I direct therefore that men pray in every place, lifting up holy hands without wrath and debate: