I have read that miracles diminish a servant's good deeds; is this true?

Extraordinary occurrences are not exclusively miracles granted to saints; rather, miracles are about adhering steadfastly to righteousness rooted in faith and piety. Therefore, anything caused by disbelief, wickedness, and disobedience originates from the extraordinary feats of God's enemies, not His saints. God may elevate a servant's status through an extraordinary occurrence if it is used in obedience to Him, or lower it if used in disobedience, or it may be permissible. True believers are those whose ranks are elevated by extraordinary occurrences if they use them in obedience to God, such as the prophets whose extraordinary feats were for establishing the religion or seeking aid in obeying God.