The devil hates priests and will do everything in his power to tempt them and bring them down.
Priests are constantly under spiritual attack. Their ministry serving the People of God is something the devil hates, and he lays out every conceivable trap to trip them up, luring them into the darkness.If a priest is not supported by his own prayer life, or the prayers of his flock, he will fall from grace, greatly damaging the faith of many people.
Here is a prayer by St. Faustina that intercedes on their behalf, asking God to protect priests from the snares of the devil.
O my Jesus, I beg Thee on behalf of the whole Church:
Grant it love and the light of Your Spirit,
and give power to the words of priests
so that hardened hearts might be brought to repentance
and return to You, O Lord.
Lord, give us holy priests;
You yourself maintain them in holiness.
O Divine and Great High Priest,
may the power of Your mercy accompany them everywhere
and protect them from the devil’s traps and snares
which are continually being set for the souls of priests.
May the power of Your mercy, O Lord, shatter and bring to naught
all that might tarnish the sanctity of priests,
for You can do all things.