Is the lack of compassion for the disabled and others considered hard-heartedness, and does this compassion contradict God being more merciful to His servants than their own mothers?

Allah judges and acts as He wills, according to His wisdom and knowledge, and upon the believer is contentment and submission. Allah tests His servants with good and evil as a trial, and upon the believer is patience and contentment. If a servant is upright, the tribulation raises their ranks and expiates their sins. But if they are disobedient, the tribulation may be a warning for them to repent, or a punishment for them in this world. Tribulation is a sunnah of life, and it may bring the servant closer to their Lord. Mercy towards those afflicted is commendable and a sign of a living heart, for believers are like one body, showing mercy and compassion to one another.