This question cannot be answered by yes or no for there is a right religion and a wrong religion. The right religion teaches the right way to salvation. What is the right teaching about the way to salvation? The Holy Scripture states that there is no savior other than our Lord Jesus.
“Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.” – Acts 4:12
Whose name was given to the people for their very salvation? In verse 10, “…by the name of Jesus Christ of Nazareth, whom ye crucified…”
A person is in the right religion if he or she is being taught the right way of salvation and has received such. It doesn’t mean that when one is religious, he or she is already saved. Our only Savior is Christ.
Will the religious person be assured of being saved? Apostle Paul revealed that they are not yet saved that’s why he prays for them. Romans 10:1-2 states that –
“Brethren, my heart’s desire and prayer to God for Israel is, that they might be saved. For I bear them record that they have a zeal of God, but not according to knowledge.”
In this verse, Paul was pertaining to those religious people for whom he was praying. Therefore, being religious is not a guarantee for a person to be saved.
What if the person is very sincere and faithful to his or her religion, is he or she already saved? He or she is not saved yet if the teaching is not according to the way of salvation taught by our Lord Jesus Christ. How much ever is the sincerity of a person in the wrong faith, his or her faithfulness can never correct this mistaken belief. The foremost thing in our faith is truth – this has no equal. We need to be faithful in the right belief for a person who is sincere in the wrong faith shall just get farther from the truth and salvation.
One example of a person who is religious but not yet saved is Nicodemus (John 3:1). Nicodemus is a Pharisees (a leader of the Jews and a teacher in Israel) but he is searching for the right way to the Kingdom of God. How will one enter God’s Kingdom? A person must be born again (John 3:5).
How will a man be born again? He must receive the Lord Jesus as his personal savior and have his sins washed away through baptism. When Peter preached in the midst of many on the day of Pentecost, the people who listened to him asked as to how may they receive salvation. Peter answered and said, “Repent and be baptized and receive the gift of the Holy Ghost (Acts 2:38).”
Our Lord Jesus Christ promised that if we repent for our sins and be baptized, we shall receive God’s forgiveness and salvation. And it is just but right that those who were already forgiven be faithful and sincere in the right religion.