But be strong, and take courage, and observe and do all the laws that my servant Moses commanded you, and do not turn aside to the right or to the left, so that you may have success wherever you go. This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to obey everything written in it. In this way, your path will be prosperous and everything will go smoothly. (Joshua 1:8-9)
Many people may have ignored this passage. But this is the real secret to a successful Christian life. And, apart from this one secret, there is no other secret. In another passage in the Bible, it is mentioned again how to make everything go smoothly.
Blessed is the man who does not follow the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of the scornful, but whose delight is in the law of the Lord, and in which he meditates day and night. He will be like a tree planted by streams, which bears fruit in its season and its leaves do not wither. Everything he does goes well.
(Psalm 1:1-3)