Are the rules of Tajwid required to be applied in a silent prayer?

Reciting the Quran with tajwid (proper intonation and pronunciation) during prayer and at other times has been explained in a previous fatwa (definition). There is no difference in this regard between audible and silent prayers. As for inviting people to Allah, it is a religiously required act, and it must be done with wisdom and good admonition, as stated in the Noble Quran: "Invite to the way of your Lord with wisdom and good instruction, and argue with them in a way that is best."