God’s default way of communicating his grace to his people — his giving us a share in his divine life —is sacramental, through the seven sacraments. Sharing in his divine life is what we were made for. So God’s way of dealing with us is a big deal for anyone who was made by God. And that is all of us. Why did he arrange things that way? I don’t know; that’s his call. But it seems like he is following up on the way he made us: spiritual and physical, social and communicative, sign-makers and sign-readers all. He invites us to share his life, but on our own level.
Does he have to follow that pattern? No. But we do. If we know about his plan, we need to live according to his plan. He can act outside it, giving his grace in ways that don’t follow the sacramental rules. He can forgive the good thief, on the cross beside his own, without a formal confession of sin; but thieves, if they are in the position to do so, must confess their sin. He can bring the unbaptized but truly good person into the glory of heaven; but the unbaptized, if they know about baptism, must come to the watery sacrament.
The Seven Sacraments of the Catholic Church are Baptism, Confession, Confirmation, Eucharist, Extreme Unction (Anointing of the Sick), Holy Matrimony and Holy Orders.