But let us take it as a clear point from the first, and not to be disputed, that religion must ever be difficult to those who neglect it. All things that we have to learn are difficult at first; and our duties to God, and to man for His sake, are peculiarly difficult, because they call upon us to take up a new life, and quit the love of this world for the next. It cannot be avoided; we must fear and be in sorrow, before we can rejoice. The Gospel must be a burden before it comforts and brings us peace. No one can have his heart cut away from the natural objects of its love, without pain during the process and throbbings afterwards. This is plain from the nature of the case; and, however true it be, that this or that teacher may be harsh and repulsive, yet he cannot materially alter things. Religion is in itself at first a weariness to the worldly mind, and it requires an effort and a self-denial in every one who honestly determines to be religious.
--Blessed John Henry Newman, Parochial and Plain Sermons
, Volume 1, “Immortality”.