Your love for God is an expression of your love for humanity. The truth is, how you relate to- and with- people determines how much you love God. If I buy a product for 1000 Naira, this reveals the value I have placed on the want or need that drove the purchase of the said product.
God placed so much value on humanity that He gave something so precious to Him, His Son, Jesus Christ to redeem humanity whom He values and requires a relationship with.

Therefore those who love humanity are expressing gratitude to God and are blessed by Him in return.

Love for humanity can only be expressed through giving.