We first read of baptism in the Bible in reference to that performed by John the Baptist. Those submitting to John’s baptism did so as evidence of their repentance over sins against the Mosaic Law.
وَكَمَا خَلَّصَ يَهْوَهُ نُوحًا مِنَ ٱلطُّوفَانِ ،‏ سَيُخَلِّصُهُمْ مِنْ نِهَايَةِ هٰذَا ٱلْعَالَمِ ٱلشِّرِّيرِ إِذَا بَقُوا أَوْلِيَاءَ .‏