Brigid of Sweden says:
" And so baptism is understood spiritually through [the metaphor of] a horse. For just as a horse, having four feet, carries a man towards completing some path, so baptism, because it is understood through a horse, carries man before the sight of God, having four spiritual effects. The first is that the baptized are freed from the Devil and are obliged to the commands and services of God. The second is that they are purged of original sin. The third is that the sons of God are also made co-heirs of God. The fourth is that Heaven is open to them."