What is Virgil's advice to Dante spoken at the gate of hell?

In canto 3, Dante and Virgil read the inscription written on the gates of hell: "Abandon all hope, ye who enter here." These words unnerve Dante, who says to Virgil that the words are "hard" for him. Virgil then tells him,

Here you must give up all irresolution.

Virgil warns him he must be very brave and put all cowardice to "death," because he is about to see very unpleasant things. The people in hell will be "sorrow laden," because they gave up goodness.
Dante goes forward toward hell in order to see "things hidden from the world."
When Charon does not want to take Dante across the river, not seeing him as one of the damned, Virgil tells him that this is a good sign that he will not end up in hell after death.
All in all, the entry into hell is a frightening prospect that Dante recoils from in dread. Virgil advises him that it is not for the faint of heart. By warning Dante to be courageous because he will see terrible things, Virgil also warns the reader of what is to come. However, for Dante, knowledge is more important than fear.

In canto 3, as Dante and Virgil approach the gates of Hell, Dante asks Virgil what the inscription above the gates means. It says, "Abandon hope, all ye who enter here." Dante is understandably frightened at this; that is why he wants to know its meaning. It might be a terrible message for him personally. Virgil, however, smiles and reassures him:

Here you must renounce your slightest doubt and kill your every weakness. Leave behind all thoughts of safety first or be shut out

As a virtuous pagan, Virgil can afford to be brave. But Dante does not have that luxury. Although not yet dead, he does still fear for the fate of his mortal soul. It is the complete absence of hope in Hell that scares Dante more than anything else. But this is all part of the learning process for him. As the journey progresses, he will grow in wisdom and become less frightened at what the next step may involve. He will also gain a better understanding of sin and how it must not be pitied.