In preparation for my "Saint of the Day" posts here is some background information on saints from the Catechism.
The intercession of the saints. "Being more closely united to Christ, those who dwell in heaven fix the whole Church more firmly in holiness...[T]hey do not cease to intercede with the Father for us, as they proffer the merits which they acquired on earth through the one mediator between God and men, Christ Jesus...So by their fraternal concern is our weakness greatly helped." (CCC 956)
The witnesses who have preceded us into the kingdom, especially those whom the Church recognizes as saints, share in the living tradition of prayer by the example of their lives, the transmission of their writings, and their prayer today. They contemplate God, praise him and constantly care for those whom they have left on earth. When they entered into the joy of their Master, they were "put in charge of many things." Their intercession is their most exalted service to God's plan. We can and should ask them to intercede for us and for the whole world. (CCC 2683)