Remember Lot's wife.
So, after you realize how poor Christ really is, and that there is nowhere to rest your head - or rather, rest on your laurels in this life; and after you finally decide to let the dead bury their dead and move on to follow Christ with resolute determination - don't forget that whoever 'puts their hand to the plow' - sets their will to do so - but keeps looking back, is unfit for the Kingdom of God.
We really need to keep that in mind...
As St. Paul explains it: "Whatever gains I had, I consider as so much loss in the light of Christ. I have come to rate all as loss in the light of the surpassing knowledge of my Lord Jesus Christ. For his sake I have forfeited everything; I have accounted all else as rubbish that Christ may be my wealth and I may be in him, not having any justice of my own... I wish only to know Christ and the power flowing from his resurrection; likewise to know how to share in his sufferings by being formed into the pattern of his death." - Philippians 3: 7-11
So, it seems to me, that if we have left behind family or friends, a career, a ministry, or a life of unbelief and/or sin, we need to consider it all as loss, that Christ may be our wealth and that we may be in him...
It's really very simple.
Revealed to little ones.
The wise and the learned
simply study it.