In this day and age of superficial religion it is common to hear preachers say that all you have to do is believe in order to be saved (from your sins and the punishment due them). The saving belief that the scriptures talk about (John 1:12) is not only believing something is true, but also committing to that truth with your actions. To believe in a good God is nice but doesn't change anything. To commit to goodness yourself changes things. God gives us the faith to believe, but it is up to us to daily act on that faith in order to be sons of God.
James 2:14-17 "What does it profit, my brethren, though a man say he
has faith, and have not works? can faith save him? If a brother or sister be naked, and destitute of daily food,
and one of you say unto them, Depart in peace, be warmed and filled; notwithstanding
you give them not those things which are needful to the body; what doth it profit? Even so faith, if it hath not works, is dead, being alone."
2:19 "You believe that there is one God; you do well: the devils also
believe, and tremble."
The first necessary act of faith is repenting (turning away from) of your sins (against God, yourself, and others). Read the following scriptures and the importance placed upon repentance:
Luke 24:46 "And [Jesus] said unto them, Thus it is written, and thus it was necessary for Christ to suffer, and to rise from the dead the third day: And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem."
Acts 2:38 "Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and you shall receive the gift of the Holy Ghost." (Baptism is an act of repentance. Baptism of babies is useless because they don't/can't repent.)
Acts 3:19 "Repent therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord".
Repenting is just inwardly rejecting the sinful behavior that you are conscious of. If you are fat from being a glutton (pigging out on food) and you know that is displeasing to God because it is bad for the wonderful gift of a body that he has given you, then you mentally/emotionally turn away from that bad habit like you would turn away from anything else that is very undesirable to you. If you are selfish and never help others in their struggle for survival then turn from that selfishness and start giving others a helping hand. If your attitude towards others is anything other than loving and supportive, then you need to turn from that attitude and be more like Jesus. Without repentance there is no salvation!