First of all it is disingenuous to state that the practice of praying for each other has no biblical foundation, we are instructed in Scripture to have a prayer life for others as it is part of God’s commandment to love one another.
(2Co 5:8 DRB) But we are confident and have a good will to be absent rather from the body and to be present with the Lord.
The Catholic Church does not teach that it is absolutely necessary for one to ask for the intercession of saints for salvation. The Church does teach that prayer to God is necessary for salvation for all believers. For a Catholic it would be wrong to ignore the liturgical worship offered to God at feast days for the saints and the prayers asking for their intercession.
The Communion of Saints is a dogma of the ancient Church and is recorded in the apostles Creed. It simply states that the faithful because of their relationship with Christ are alive even after the death of their flesh and worship with us. To us the Church is made up of the Church militant who represents all those believers living out their hope in the flesh.
(Phi 2:12 DRB) Wherefore, my dearly beloved, (as you have always obeyed, not as in my presence only but much more now in my absence) with fear and trembling work out your salvation.
(Phi 2:13 DRB) For it is God who worketh in you, both to will and to accomplish, according to his good will.
It consists of the Church Suffering who are those who are temporarily in need of further purgation from sin so that they may enjoy the presence of God.
(2Ma 12:46 DRB) It is therefore a holy and wholesome thought to pray for the dead, that they may be loosed from sins.
Lastly, the Communion of the Saints consists of those who have won the race:
(Phi 3:14 DRB) I press towards the mark, to the prize of the supernal vocation of God in Christ Jesus.
Their immortal souls are in heaven in God’s presence:
(Rev 5:8 DRB) And when he had opened the book, the four living creatures and the four and twenty ancients fell down before the Lamb, having every one of them harps and golden vials full of odours, which are the prayers of saints.
The universal stream connecting all of God’s creation is His love, which we take on in our baptism into our journey towards sanctification. This is not an emotional but a desire placed in us by the Spirit of God that endures as a desire for those other than ourselves and this love extends even to our enemies. This is truly a love that comes only from God and is a foreign concept and nonsense to those who have not received God’s salvific grace. This desire within our souls does not end with the death of our flesh but continues into eternity where the saints through their intercession in prayer encourage us in our race and assist us to endure unto our union with God.
I think that some people of faith, who do not understand the Communion of Saints, somehow believe that asking saints to pray for us is detracting from our love or our trust in God. In truth it is impossible, if we truly love as God commands and has given us the grace to understand, not to pray to those whom we love and in turn we expect them to return that same love to us by praying for us and presenting our prayers to God.