I have heard that salvation is by faith, and I've also heard that it is by grace.
Question:
Is faith itself something we choose or is it also given by grace?
If the answer is that faith is a gift of grace:
I lack faith in Christianity, though I am trying to understand. If I lack faith, is there no way to get it unless God decides to give me this faith?
Why is faith withheld from so many?
You have, like everyone else, have been given (by God) the ability to exercise faith. Now what you use your faith to trust in, is what you come to conclusion is true (by listing to and studying the evidence presented).
For an example do you believe men went to the moon, if you do you have exercised faith in the testimony of nasa, government and a few men.
But since you did not actually participate in going to the moon by getting in a rocket and flying there. You have to accept by faith that what they are saying is true. I personally do not believe people went to the moon, so see not everyone believes this.
So everyday faith that every person possesses, is what is used to receive Gods free gift of Eternal Life. This free gift God is offering of Eternal Life, is an example of Gods grace.
That there is nothing by any actions a person can do to bring about this free gift of Eternal Life. God just by His grace is ready to give this free gift of Eternal Life to anyone who believes.
Going to church for a life time or being the best person that is possible will not get a person this gift. It is only received when a person examines the evidence presented by and in the Bible. And comes to believe that the evidence presented in the Bible is true.
That Jesus was who He said He was, The promised Messiah from the prophecies of The Tanakh and that Eternal Life is by trusting in The Messiah for Gods free gift of Eternal Life (John 11: 25-27).
John 3:14,15 And as Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up, that whoever believes in Him should not perish but have eternal life.
John 3:16 For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
John 3:17 For God did not send His Son into the world to condemn the world, but that the world through Him might be saved.
John 3:18 “He who believes in Him is not condemned; but he who does not believe is
condemned already, because he has not believed in the name of the only begotten Son of God.
John 3:36 He who believes in the Son has everlasting life; and he who does not believe the Son shall not see life, but the wrath of God abides on him.”
John 5:39,40 You search the Scriptures, for in them you think you have eternal life; and these are they which testify of Me. But you are not willing to come to Me that you may have life.
John 11: 25,26,27 Jesus said to her, “I am the resurrection and the life. He who believes in Me, though he may die, he shall live. And whoever lives and believes in Me shall never die. Do you believe this?”
She said to Him, “Yes, Lord, I believe that You are the Christ, the Son of God, who is to come into the world.