In order to be saved, a human person must die in the state of sanctifying grace. All persons who die in the state of grace will have eternal life in Heaven, though they may have to pass through a time of purification in Purgatory. All persons who die without the state of grace will not have eternal life in Heaven.
We poor fallen sinners are conceived without the state of grace, due to original sin. So we must obtain the state of grace in this life, and die in that state. But the only way for us to be cleansed of original sin and enter the state of grace is by some form of baptism. There are three forms of baptism:
1. the formal Sacrament of Baptism with water
2. a baptism of desire, which can be implicit
3. a baptism of blood
Christians enter the state of grace by the Sacrament of Baptism, often as infants or young children. A Christian who is baptized as an adult may actually have entered the state of grace by a baptism of desire, prior to their baptism with water.
A baptism of blood is received by catechumenates who die for the Christian Faith prior to formal baptism. But in such a case, the person enters the state of grace prior to death. God grants the state of grace in view of their impending death.
My theological opinion is that all prenatals, infants, and young children are given a baptism of blood, prior to death, by Jesus Christ dying on the Cross, in view of their impending deaths. So they die in the state of grace. The opinion that they go to limbo, to a state of perfect natural happiness, is untenable at this point in the development of doctrine.
A baptism of desire can be obtained without explicit desire for the Sacrament of Baptism. This was the primary means of salvation prior to the establishment of formal baptism. And it is still a common path of salvation today. For God wills all human persons to be saved (the universal salvific will), and therefore He must make salvation concretely available to all.
An atheist, who spurns formal baptism and belief in God, might enter the state of grace by an implicit baptism of desire, by loving his neighbor selflessly. An act of love is sufficient to substitute for the lack of formal baptism. But if the atheist instead hates his neighbor, he sins mortally and must repent to enter the state of grace.
If any human person fails to obtain the state of grace in this life, despite ample opportunity, he is guilty of an actual mortal sin of omission, and therefore is condemned to Hell (if he dies unrepentant).
If any human person enters the state of grace, but then leaves that state by an actual mortal sin, repentance is needed to return to the state of grace. Imperfect contrition and a valid reception of the Sacrament of Penance returns a person to the state of grace. Otherwise, perfect contrition is needed to return to the state of grace. But perfect contrition can be implicit. An atheist can return to the state of grace after actual mortal sin by contrition out of love of neighbor. All true love of neighbor includes, at least implicitly, the love of God.
All persons who die unrepentant from actual mortal sin will be punished forever in Hell. All persons who die in a state of grace will have eternal life in Heaven, perhaps after a temporary stay in Purgatory.
All persons in a state of grace have the three infused theological virtues: love, faith, hope. So all persons in the state of grace have received some form of baptism and they have faith — a faith enlivened by love and inspired by hope.
If a baptized person commits an actual mortal sin, and thereby falls out of the state of grace, he loses the infused virtues of love and hope, but typically he still retains the virtue of faith. This faith is a true virtue, which can guide him back to the state of grace by guiding him to repentance. However, this faith is not enlivened by love and hope, until and unless he repents. (The infused theological virtue of faith can be lost, along with love and hope, by a grave sin against faith, especially by the sin of apostasy.)
Some persons have been baptized, and they die with the virtue of faith, yet they are condemned to Hell. For their faith is not enlivened by the true love of God and neighbor. They died unrepentant from actual mortal sin. So baptism and some form of faith was not sufficient to save them.
All persons who die in the state of love, faith, and hope will have eternal life. For the state of grace always includes love, faith, and hope. An atheist who has the state of grace by loving his neighbor has an implicit faith. By his faith in the love of neighbor, in truth, justice, mercy, and goodness, the atheist exercises the theological virtue of faith. So an atheist can be saved by an implicit baptism of desire and implicit faith, as long as he has the true love of neighbor. No human person can possess the infused theological virtue of love, without also having the other two infused virtues of faith and hope.
Is baptism required for salvation? Yes, baptism is required for salvation in some form, including implicit baptism of desire or baptism of blood. For baptism is how persons conceived in original sin enter the state of grace.
Is faith required for salvation? Yes, each form of baptism gives the human person the gifts of love, faith, and hope as part of the state of grace.
Are baptism and faith sufficient for salvation? If it is a living faith, enlivened by love and inspired by hope, then faith is sufficient. But if it is the dead faith of a baptized persons who is unrepentant from actual mortal sin, then that type of faith is not sufficient.
All human persons who die in the state of grace, which is the state of love, faith, and hope, will have eternal life. All human persons who die in a state of loving God, necessarily have the state of grace, so they will have eternal life. All human persons who die in a state of loving their neighbor, with a true selfless love, necessarily have the state of grace, so they will have eternal life.
The Pharisees of today, who have been formally baptized and who have the virtue of faith, but who also are unrepentant from actual mortal sin, will not have eternal life — unless they repent. For faith must be enlivened by the love of neighbor in order to be the living faith that saves.
Please take a look at this list of my books and booklets, and see if any topic interests you.