"Seated at the right hand of the Father" and pouring out the Holy Spirit on his Body which is the Church, Christ now acts through the sacraments he instituted to communicate his grace. The sacraments are perceptible signs (words and actions) accessible to our human nature. By the action of Christ and the power of the Holy Spirit they make present efficaciously the grace that they signify.
Source: Catechism of the Catholic Church (Vatican.va)