The truth of unseen is accepted by believers without an iota of doubt, they believe in the unseen, as ordained:
‘’Those who believe in the unseen, and perform the prayers, and give from what We have provided for them. And those who believe in what was revealed to you, and believe in what was revealed before you, and are certain of Hereafter. These are upon guidance from their Lord. These are the successful ’’ (02:03, 04 & 05)
Their belief in the unseen makes them pray, and out of what Allah provides, they make provision for others. The believers believe in what was revealed to Prophet Mohammad (PBUH) and in what were revealed to the Prophets before him, and they are certain about what the Divine Code says about Hereafter. Since they act upon guidance from their Lord and what the Divine Code entails, they tread upon the path of success.
There is another set of people however—the disbelievers, warned or not about consequences of disbelief, they continue on the path, which is full of torment:
‘’As for those who disbelieve; it is same for them whether you have warned them, or have not warned them; they do not believe. God has set a seal on their hearts and on their hearing, and over their vision is a veil. They will have severe torment. (02: 06 & 07)
The disbelief hardens their hearts; the seal noted in Ayah Kareem pertains to total lack of perception vis-à-vis the Divine Code. Neither do they perceive what the Divine Code entails, nor does their sense of hearing remain tuned to it, and over their vision remains a veil depriving the sense of sight to visualize the path of sanity.