Fiqh-us-Sunnah Volume 2, Supererogatory Prayer, Fiqh 2.129.

It is preferred for one to go early to the salatul Jumu’ah, unless he is the imam. ‘Alqamah says: “I went with ‘Abdullah ibn Mas’ud to the mosque and we found that three people had arrived there before us. [Ibn Mas’ud] said: ‘The fourth of four, and the fourth of four is not far from Allah, for I have heard the Messenger of Allah say: “The people will be seated on the day of resurrection according to how they came to the salatul Jumu’ah: the first, then the second, then the third, then the fourth and the fourth of four is not far from Allah.”‘ This is related by Ibn Majah and al-Munzhiri.

Abu Hurairah reports that the Prophet said: “Whoever makes ghusl on Jumu’ah like the ghusl one makes due to sexual defilement, and then goes to the mosque, it will be as if he had sacrificed a camel. If he goes during the second hour, it will be as if he had sacrificed a cow. If he goes during the third hour, it will be as if he had sacrificed a horned lamb. If he goes during the fourth hour, it will be as if he had sacrificed a hen. And if he goes during the fifth hour, it will be as if he had sacrificed (something like) an egg. When the imam comes, the angels will be present to listen to the remembrance.” This is related by the group, save Ibn Majah.

Ash-Shaf’i and a number of scholars are of the opinion that the “hours” refer to the hours of the day; therefore, it is preferred for the people to start attending the mosque right after dawn. Malik is of the opinion that it refers to portions of the hour before the sun passes its meridian and afterward. Some hold that it refers to portions of the hour before the sun passes its meridian. Ibn Rushd says: “That is the most apparent meaning as going [to the mosque] after the sun passes the meridian is obligatory.”