The truth is, God will heal me of my diseases, ailments, and weaknesses, of heart, mind, and body. He will make me sound and whole. This is because of the greatness of His love, grace, and mercy, and not because I merited His healing by works. This is the truth that the Bible teaches. Thoughts and feelings of sickness are lies which the enemy lies to us. Anything which contradicts the infallible truth of the Word of God is a lie. We do not have to accept those lies. We can reject the lies and believe the truth instead.
This is how I trained my heart and mind to receive and believe the truth:
“I am feeling __infirm__, but it is only a feeling brought on by my past. It is not a true reflection of my current reality. My reality is determined by the word of God, and this is what it says: __repeat Scripture__.”
The word of God is powerful, living and active, the weapon of our warfare which is effective against all the lies of the enemy and mighty to tear down strongholds (2 Cor 10:4).