We shouldnt be pleading for missionaries.

Since 1973, I have been living in the United Kingdom, and
seeking to present the desperate need of the three thousand
million people, alive today, who have never yet heard of our
Lord Jesus Christ and of the redemption He wrought for them
at Calvary. These are the “hidden peoples” in more than ten
thousand ethnic groups around our world. As I try to present
their needs, I pray earnestly that the Holy Spirit will stir hearts
to make a response. It seems so obvious to me that Christian
young people . . . should rise up and go. . . .”
Why is the response so poor? . . .
Is it that we Christians today have an inadequate understanding
of God’s holiness and therefore of His wrath against
sin and of the awfulness of a Christless eternity? If we were
gripped by the two facts—of the necessity for judgment of sin
because God is holy; and of the necessity of holiness in the
Christian that he may represent such a God to others—would
we not “hunger and thirst after righteousness” whatever the
cost, and would not others then see Christ in us, and be drawn
to Him?
In other words, if we [understood] the Scriptural teaching
on the need of Holiness in the life of every believer, we should
not need to plead for missionaries.

_Roseveare, Living Holiness, p. 32.