If a devotee takes to Krsna Consciousness very seriously and sincerely but if he falls down due to some reason, Krishna never forgets that sincere service rendered. If we have pleased Him or His devotee, Krishna will never forget that and He will intervene and give us the chance again and again may be in this birth or some future birth. It depends on us whether we use our free will to surrender to the Lord or to surrender to our material desires. But once we establish the relationship, He will never let us go for long.
There was once a devotee who left Krsna Consciousness and wanted to enjoy material life. He flew to another country and as soon as he came out of the airport, one devotee came and asked him to buy a book. He just ignored and thought to himself that why is Krishna doing this. When he entered His hotel room and switched on the television, on some news channel He saw devotees chanting the Lord’s blissful names. Whatever He did, wherever he went somehow Krsna kept reminding Him of the transcendental life he had given up for the poisonous nectar of this world.
That’s when He understood that Krishna is so merciful and kind that He is never going to let me go irrespective of my foolishness and disobedience. At that same point, that devotee returned back to the temple and dedicated himself whole-heartedly in the service of the Lord.
(HH Radhanath Swami)