Human beings only know about Allah ﷻ that which He has decided to reveal about Himself. And with that revealed knowledge, a person will only be able to accept it as truth if Allah ﷻ allows that person to accept it. For a believer, these are two immense blessings from Allah ﷻ. Allah ﷻ could have chosen to not send any Messengers, yet still hold human beings accountable in the hereafter for having to recognize Him through His signs alone. But out of His mercy, He revealed this information clearly to mankind. However, despite this open access to the knowledge of Allah ﷻ, there are very few people whose hearts are given the ability to accept it as truth. Allah ﷻ, out of His tremendous mercy, allowed us to be among those who do accept it. He ﷻ is deserving of our gratitude for many things, but among the most important of these is His opening our hearts to recognize and accept His greatness.