3 By this his aged guide in presence came;
By this > At this; by this time
4 Who, soon as on that knight his eye did glance,
soon > [as soon]
5 Eftsoons of him had perfect cognizance,
Eftsoons > Forthwith cognizance > recognition (SUS)
6 Sith him in Faery court he late advised;
Sith > Since late > recently advised > saw, noticed, observed
7 And said, "Fair son, God give you happy chance,
happy > fortunate; happy