There are three reasons why we need the guidance of the prophets:

1. The need we have for their teachings; The universe is not created uselessly and God didn't need it, rather He created it to have mercy upon us so that we reach our perfection; on the other hand, we cannot reach that perfection without His errorless knowledge given to us by revelation to the prophets.

2. To realize and accomplish the goal of creation, we need errorless guidance and, our intellect alone is not capable of treading this path.

3. The need for a guide in social and moral issues

We need a perfect teacher and a model to teach us how to control our instincts and build a perfect society; an infallible and pure person is the best choice by which God shows His mercy.

- Trustworthiness of the prophets is a reason for the infallibility of the prophets. It's so that people can trust their prophets and messages and be guided to perfection which is the goal of their creation.

- There are two criteria for evaluating the claims of prophethood:

1. Studying the content of the prophet’s invitation and message and collect trustable signs.

2. Miracles that are supernatural.

- Conditions of a Prophet’s Miracle

1. Normal people and even the most genius must not be able to do the same.

2. The miracle-maker must be so certain of it to be able to challenge others to try.

3. The miracle must be connected as proof to the claim of prophethood.