What is the significance of the 2 different tenses?

Revelation 14:4 These are they which were not defiled with women; for they are virgins. These are they which follow the Lamb whithersoever he goeth. These were redeemed from among men, being the firstfruits unto God and to the Lamb.

  5 And in their mouth was found no guile: for they are without fault before the throne of God.

These "are" they (present tense)

Which "were not" defiled (past tense)

they "are" virgins  &  These "are" they (present)

These "were redeemed" (past)

"was found" no guile (past)

they "are without fault" (present)