How did the Companions learn faith before the Qur’an, how did their faith increase with the Qur’an, and how can a Muslim today achieve that?

The Companions, may Allah be pleased with them, received faith from the Prophet, peace and blessings be upon him, as he cultivated it within their souls through his guidance and instruction. The Quran then increased them in faith. Learning faith was not merely a theoretical lesson, but rather an experience of living with the revelation and its bearer, which made them the most discerning of people and the least pretentious. Faith is attained by turning towards Allah, holding oneself accountable, adopting the means that increase faith, avoiding the causes of its decrease, and keeping company with people of goodness and righteousness.