"My heart is fixed, O God, my heart is fixed; I will sing and give praise."
To have a fixed heart means to have our mind made up so tha we are not going to change it. If we are going to experience any kind of victory andd be positive in our lives, we must be determined. If we are going to see the fulfillment of Heavenly Father's will, walk in or follow the leading of the Holy Ghost, or accompolish anything worthwhile in this life, we must set our face like flint.
And we must understand that the adversary is not going to roll out a red carpet for us just because we decide to get saved and serve our Father in Heaven. He is going to oppose us at every turn.
The problem is that because of the mentality of our society, we are always looking for something easy. We have to be determined to do the will of God, to stay positive and happy, and to walk in His peace. His will won't just happen in our life. We are partners with Him, and we must do our part. Part of what hwe have to do is never give up!