And now, O Israel, what does the LORD your God ask of you but to fear the LORD your God, to walk in all his ways, to love him, to serve the LORD your God with all your heart and with all your soul.
We don’t often equate love and fear together. At least in the English language the two seem to be opposites. A person who is afraid of snakes isn’t going to love them.
In regard to God however, fear carries a different meaning. Fear means a complete respect and a reverence for God. It is an acknowledgement of the power of God but not a terror of Him. The closest earthly equivalent may be a police officer. We don’t fear them in the sense that we are afraid that they are going to harm us but if we must interact with a police officer we will be sure to be on our best behavior and not give them any reason to arrest us either.
When we fear God, we show Him the respect and reverence that is due to Him. When Moses encountered God he was told to remove his sandals because the place that he was standing was holy ground. In the Old Testament the Ark of the Covenant was never to be touched and in an instance when it was, the offender was struck dead instantly.
Part of loving God is respecting Him. In short, sometimes we don’t take God seriously enough. We don’t think of Him as the One who judges sin and punishes the wicked in hell. Instead we sometimes overlook sin with an attitude of it being ok because God will forgive it. We must take God seriously and reverently. This is what it means to fear Him.