Fervently

means,

Excited; glowing; very warm;
lively; full of spirit; eager;
passionate; zealous.

(From a Latin word meaning,
"To be hot; to boil; to glow".)

Seeing ye have purified your souls
in obeying the truth through the Spirit
unto unfeigned love of the brethren,
see that ye love one another
with a pure heart fervently:
Being born again, not of corruptible seed,
but of incorruptible,  by the Word of God,
which liveth and abideth forever.

1 Peter 1:22 & 23