The most important lesson in Christian life!
In our Christian Journey we always learn and never finish learning until we reach our destination, being with our heavenly Father and his Son Jesus Christ. But to me, the most important lesson to learn and to practice and train is to; 
W​hether it's small or big, earthshaking or unnoticeable, affects only you or many around you, learn to cling to Christ!
And the amazing truth is; since Jesus died on the cross for all of my sins, gave his life for me I really CAN rely on him about everything! And since God made all these great and precious promises to me and you, and  he ever breaks any of his promises, he is 100% trustworthy!
Growing up in this world, we learn to rely on ourselves about everything. And we see where that leads...Now in Christ, we learn to depend on our heavenly Father instead of ourselves. The Holy Spirit, by faith leads us to trust our Heavenly Father in everything. Since we may be babes, children or growing up in Christ, naturally our flesh drags us back to our old habits; "doing things our way". So I encourage you and me to practice clinging to Jesus about everything.
This is what Spurgeon said; it is alot harder for him not to trust Jesus than to trust Jesus, because he never failed him. (quoted in my words)
This is not a matter of one day. The scriptures tell us to run the race set before us; does not a righteous man fall 7 times and rise again. We all fail many times, but the point is to get back up and cling to Jesus! And get back up and cling to Jesus!​​