When, for instance, New Testament states firmly, "Except a man hath received the baptism of water and of the spirit, he cannot enter into the Kingdom of God," it is referring to divine teachings as the heavenly grace and mercy of God. These are what have purified the hearts of mankind through the ages.
Of course, arguing about the meanings of words is also age old, and given how old many religious texts are, and from what diverse language idioms and cultures, there can be much fodder for debaters! 'Abdu'l-Bahá, the son of Bahá'u'lláh and His appointed Interpreter, explained it this way:
"In the Gospel according to St John, Christ has said: 'Except a man be born of water and the Spirit, he cannot enter into the Kingdom of Heaven.'[1 St John iii, 5] The priests have interpreted this into meaning that baptism is necessary for salvation. In another Gospel it is said: 'He shall baptize you with the Holy Ghost and with fire'.[2 St Matthew iii, 11] Thus the water of baptism and the fire are one! It cannot mean that the 'water' spoken of is physical water, for it is the direct opposite of 'fire', and one destroys the other. When in the Gospels, Christ speaks of 'water', He means that which causes life, for without water no worldly creature can live--mineral, vegetable, animal and man, one and all, depend upon water for their very being...He is symbolizing that which is the cause of Everlasting Life. This life-giving water of which He speaks is like unto fire, for it is none other than the Love of God, and this love means life to our souls. By the fire of the Love of God the veil is burnt which separates us from the Heavenly Realities, and with clear vision we are enabled to struggle onward and upward, ever progressing in the paths of virtue and holiness, and becoming the means of light to the world." - Paris Talks, p. 81While traveling in the West, 'Abdu'l-Bahá answered many questions about Church rituals, some of which still divide Christian denominations. His purpose was to help people understand the symbolism behind the rites and to ease them into the core of unity not only among various churches, but also across all religions. About baptism, he said:
"The principle of baptism is purification by repentance. John admonished and exhorted the people, and caused them to repent; then he baptized them. Therefore, it is apparent that this baptism is a symbol of repentance from all sin:... the return from disobedience to obedience. Man, after remoteness and deprivation from God, repents and undergoes purification...Therefore, the spirit is the bounty of God, the water is knowledge and life, and the fire is the love of God....the Spirit becomes sanctified, good and pure--that is to say, the reality of man becomes purified and sanctified from the impurities of the world of nature. These natural impurities are evil qualities: anger, lust, worldliness, pride, lying, hypocrisy, fraud, self-love, etc....But in the cycle of Bahá'u'lláh there is no longer need of this symbol; for its reality, which is to be baptized with the spirit and love of God, is understood and established." - Some Answered Questions, pp. 91-92Bahá'ís believe that "The Prophets come into the world to guide and educate humanity so that the animal nature of man may disappear and the divinity of his powers become awakened. The divine aspect or spiritual nature consists of the breaths of the Holy Spirit. The second birth of which Jesus has spoken refers to the appearance of this heavenly nature in man. It is expressed in the baptism of the Holy Spirit, and he who is baptized by the Holy Spirit...becomes just and kind to all humanity; he entertains prejudice and ill will toward none; he shuns no nation or people." - 'Abdu'l-Bahá, The Promulgation of Universal Peace, p. 41
Let us all become baptized with the water of life--the Holy Spirit--little by little, day by day!