This is what I believe and I catch flack from both sides, Calvinists and non-Calvinists , but so be it!
The faith is in the message of the Gospel.
Remember Paul said, faith comes by hearing and hearing by the Word of God.
When a person hears the Gospel that Paul preached and shame on our preachers who don't preach that same Gospel, the Holy Spirit works from that hearing making the truth of the Gospel real in the heart.
If man accepts that Gospel then the Holy Spirit provides with that conviction the faith needed to believe unto eternal life.
Paul said that, "from the heart man believes unto righteousness."
The heart is convicted, the heart believes, and righteousness is imputed through that faith.
When you do a sturdy of the word gospel it is called the gospel of the kingdom in 5 verses. Mt 4:23, 9:35, 24:14, Mk 1:14,15. The gospel then become the glad tidings or good news of the kingdom of God revealed or put in order. Christ then goes on to reveal it saying the kingdom of God is "like unto" in Mt 13:31, 33. 44, 45, 47. 52, 18:23, 20:11, 22:2, and 25:1. The kingdom of God is mentioned 54 times in the 4 gospels.
In Matthew 6:33 Christ tells us to "seek ye first the kingdom of God and his righteousness." This is included in instruction of how men might not perish but be preserved in a sure house. Mt 16:18
Since the Lord never leaves his people alone to wander around by themselves, and his part of his covenant is to gather his people together ( Jer 32:37-44, Ps 147:2, Isa 56:8 to name a few) how do we teach the gospel in the context of the righteousness of Christ and leave out the teachings of the kingdom? How can the heart of man believe unto righteousness and not be taught it in the context of the kingdom. Christ went to great lenght to instruct his disciples on how to recognize the true kingdom of God. To teach that salvation can be received and the teaching of the kingdom not be necessary would seem to negate an important part of the doctrines of faith and salvation.