Faith is a gift of God, but doubt is a choice. Doubt is a result of thoughts formed in the mind that are in direct opposition to God's Word. That is why it is so important for us to know the Word of God. We are immediately able to discern the devil's lies when we know the Word.
Doubt is just another part of the devil's arsenal of weapons aimed against our minds. We can choose our thoughts. We have the option to decide whether to accept or reject our thoughts. That means when doubt knocks on the door of our minds, we have the option of inviting it in or calmly but firmly dismissing it. The choice is ours. We can believe or we can doubt. And we know the path of believing leads to the blessings of God.
Matt 28:16-20
Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed and made appointment with them. And when they saw Him, they fell down and worshiped Him; but some doubted. Jesus approached and, breaking the silence, said to them, All authority (all power of rule) in heaven and on earth has been given to Me. Go then and make disciples of all the nations, baptizing them into the name of the Father and of the Son and of the Holy Spirit, teaching them to observe everything that I have commanded you, and behold, I am with you all the days (perpetually, uniformly, and on every occasion), to the [very] close and consummation of the age. Amen (so let it be).
- Excerpt from Joyce Meyer's Daily Devotionals -