Because Christianity and Vaisnavism are both personalist philosophies, they are quite similar in nature. The Vedas teach that the son is non-different from the father and similarly, Christian theology teaches that Christ, the son of God, is also God. While Christ says "I am the son of God", He never says, "I am God." This is in agreement with the acintya-bhedabheda-tattva philosophy given by Lord Caitanya, that the Lord, due to his inconceivable potencies, is simultaneously one and different. Christianity is a form of Vaisnavism because God is recognized, and Christians practice bhakti-yoga when they worship Jesus Christ because they are accepting him as the son of God and are therefore accepting God. Christ preached that the topmost relationship is a direct, personal loving relationship with the Lord.
Like the Vaisnavas, Christ was always compassionate and anxious to save humanity from suffering. Christians believe that through His crucifixion, Jesus Christ assimilated all the sinful activities of the world's people. One of the most significant differences between Christianity and Vaisnavism is that Christianity does not accept the Vedic conclusion on reincarnation, or transmigration of the soul. Christian doctrine holds that there is heaven and hell (akin to the divine and demoniac natures), but Christianity teaches that upon death of the body, the spirit soul does not return to a new earthly body. If, during his lifetime, the individual comes into relationship with God the Father through Christ the Son, then all sins are forgiven and the individual goes to Heaven. There is a process of confession and atonement, and atonement is required and must be undergone according to the gravity of one's sinful acts. According to the Vedic conclusion, however, everyone is responsible for his own sinful activities. While the spiritual master may mitigate a disciple's sins, if one continues to commit sinful acts he will reap the reaction, or karmic effect, in this lifetime or in future lifetimes.
Christ consciousness is also essentially Krsna consciousness, but at present people do not follow the rules and regulations of Christianity (the commandments of Jesus Christ), consequently they do not come to the standard of God consciousness. For example, the Bible contains the commandment "Thou shall not kill," but Christians have built the world's best slaughterhouses. This is another of the most significant practical differences between Christians, who encourage killing other living entities for food, and Vaisnavas, who follow strict standards of vegetarianism.
Bhaktivedanta Book Trust. Excerpted from various texts and purports of HDG A.C. Bhaktivedanta Swami Srila Prabhupada.