This verse states that many or all are invited to the wedding feast of God but not everyone who wants to come will accept the terms of the invitation. They must put on the robe of God or they will be thrown out of the place that they want to be. You are chosen because of your willingness to accept the King's terms of admittance.
Some people are intrigued by the invitation of God to have fellowship with Him and want to enjoy the wonders of God but are not wiling to admit that their life is not worthy of admittance into this fellowship. They try to maintain that they should be accepted on their own merits. Unfortunately each person's own merits will get them thrown out of the banquet.
If you hear the call of God on your life, then respond and realize that you must accept Jesus Christ's death for you as your covering or you will be thrown out of the very fellowship that you were intrigued by.