Thomas has his faith only when he saw it and have believed.
John 20:29 Jesus said to him, “Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed.”
Others acquired their faith by just hearing the word of God although not seen yet they have believed.
Romans 10:17 So then faith comes by hearing, and hearing by the word of God.
But faith alone without works can not save.
James 2:14 What does it profit, my brethren, if someone says he has faith but does not have works? Can faith save him?
James 2:17 Thus also faith by itself, if it does not have works, is dead.
The evidence that you have faith of things not seen are your works following what God has commanded with a complete trust in the hope to everlasting life. Same with God where the evidence of things not seen are His marvelous works.
Hebrews 11:1 Now faith is the substance of things hoped for, the evidence of things not seen.
Let us therefore put ourselves the way Christ Jesus thought of himself. This is the ultimate and the highest form of faith a Christian should achieve.
Philippians 2:6-8 who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men. And being found in appearance as a man, He humbled Himself and became obedient to the point of death, even the death of the cross.
It may be true that one has to have faith in Christ but it is holy and pure if you have the faith of Christ Jesus himself.
Galatians 3:27 For as many of you as were baptized into Christ have put on Christ.
And Jesus said:
Matthew 12:50 For whoever does the will of My Father in heaven is My brother and sister and mother.”
And one will of the Father is this:
Matthew 5:32 But I say to you that whoever divorces his wife for any reason except sexual immorality causes her to commit adultery; and whoever marries a woman who is divorced commits adultery.
Matthew 19:9 And I say to you, whoever divorces his wife, except for sexual immorality, and marries another, commits adultery; and whoever marries her who is divorced commits adultery.”
How dare you to call Him Brother when you have a selective faith. Worst if your work is justified by evil men and you.
James 2:10 For whoever shall keep the whole law, and yet stumble in one point, he is guilty of all.
James 3:2 For we all stumble in many things. If anyone does not stumble in word, he is a perfect man, able also to bridle the whole body.
1 John 2:5 But whoever keeps His word, truly the love of God is perfected in him. By this we know that we are in Him.
But God is justice and love. If you did it out of ignorance then you are forgiven.
James 4:17 Therefore, to him who knows to do good and does not do it, to him it is sin.
But as Manny Pacquiao said, Now You Know.