Roshzsas
Da'wah or calling others to Islam is the best of deeds, because it involves guiding people to the Straight Path and to that which will bring them happiness in this world and in the Hereafter.
Oh, my dear brother and sister, you need to carry the message of Islam in your daily life. It should show in your character, your dealings with others, your business transactions, and in your everyday tasks; otherwise, our Prophet may serve as a witness against you on the Day of Judgment, and you could potentially get punished for your neglect of this vital and important life task.