The Sacraments are efficacious signs instituted and given to the Church by Christ.
In the sacraments, we meet Christ and he gives us Sanctifying Grace.
The sacraments act ex opera operato. This means that the sacraments unfailingly give grace because Christ works through them.
Sanctifying grace is a free gift of God which allows us to become children of God, to share in the divine nature, and to inherit eternal life.