How can we reconcile the benefit or harm caused by a creature with the fact that Allah is the One Who benefits and harms, and does the latter lead to the doctrine of predestination (Jabr)?

God alone possesses the power to harm and benefit, to give and to withhold. This does not negate the servant's ability to benefit or harm another in what God has enabled him to do, for God is the true Giver, and the servant gives by acquisition. The servant has a will and choice with which he performs actions, and based on them he will be held accountable and rewarded. God knows what will be from the servant without compelling him to evil. Arguing by predestination (qadar) is invalid, both rationally and Islamically. The Muslim should stay away from excessive whispers and delving too deeply into matters, and instead increase in the remembrance of God, purity, and prayer.