19 Now that those who hate God are zealously bringing their insidious attacks to bear upon this great continent, other serious difficulties have arisen to hinder the spread of the Gospel in certain districts of Africa. Of course, you know the religious tenets of those people who, although they are quick to profess that they worship God, nevertheless are easily attracting and enticing the minds of many into another path which is not that of Jesus Christ, the Savior of all nations. Our heart, which is that of the common Father of all, is open to every man of good will; but We, who are the representative on earth of Him, Who is the Way, the Truth, and the Life, cannot contemplate such a situation without great sorrow.
Source: Fidei Donum (Vatican.va)