If one takes refuge in the Three Gems and one is a true Buddhist one cannot be reborn in the four lower realms. This is reiterated many times by the Buddha in his various discourses.
Not only he wouldn’t reborn in the four lower realms he will also excel in ten qualities over other devas when he is reborn as a deva. The ten qualities are: longevity, fine physical appearance, physical and mental well-being, good companionship, power and enjoyment of the five senses.
The Buddha preached in the Velama Sutta that a Buddhist who has established himself in the Triple Gems will enjoy more benefit than a person who makes unlimited and incomparable offerings.
At the time of Gautama Buddha, the Prince Ajatasattu was in a state of great agitation for his heinous offence of killing his father. If he dies, he will be certainly reborn in niraya. After he had the chance of paying homage to the Buddha and taking refuge in the Three Gems, he became peaceful and calm. As a wise supplication or appeal changes a death-sentence to a life-sentence, the act of taking refuge in Triple Gems changed the destiny of the Prince Ajatasattu from being reborn in Maha-avici (the lowest and worst in eight nirayas) to being reborn in Lohakumbhi (iron cauldron hell). His faith in the Three Gems was unexcelled among the worldlings. According to the words of Buddha, he will be a lesser Buddha (Pacceka Buddha) by the name of Vijitavi, on account of his great merit of taking refuge in the Triple Gems.
One who takes refuge in the Triple Gems can enjoy eight benefits in his every future existence. These benefits are:
1. Being honoured and venerated by many people;
2. Being endowed with great wisdom;
3. Having influence on others to conform one’s wish;
4. Having great wealth;
5. Having good physical appearance;
6. Being loved and respected by many people;
7. Having good and loyal friends;
8. Having great fame.
Moreover, taking refuge in the Triple Gems is the gateway to the Middle Path that leads to liberation from the round of rebirths, and it is the Initial Excellence of being a Buddhist. The benefits described above illustrate the Excellence in the middle stage, and to be finally liberated from Samsara represents the Final Excellence of being a Buddhist.