There are four numbers particularly linked with the Holy Spirit, who in Christian theology is understood to be the third Person of the Blessed Trinity, co-equal and co-eternal with the Father and the Son. These numbers are three, seven, 12 and 50.
Three because He is the Third Divine Person, Divine Love Personified who unites the Trinity. His three key attributes are Love, Union and Gift. And his great gift, called sanctifying grace, is ultimately a gift of Himself to us. This grace comes with three principal infused virtues, namely faith, hope and charity, called Theological because they have God as their proper object.