You get moving!
A lot of books have been written, videos made on the subject of staying in shape. And a lot of people spend a lot of time and money getting their bodies in top form and keeping them that way. It's a big step toward healthier lifestyle and a longer lifespan.
Did you know that spiritual fitness is even more important than it's physical counterpart? The scriptures tell us to "Stir up the gift" in II timothy 1:6. It's important to keep the wheels and cogs greased up so that we can "be ready always to give an answer to every man..." in I Peter 3:15.
Bro. Green goes to the gym about 4 times a week to work out, and I like to go with him to stay on my A game physically. It's rough stuff sometimes. Especially when you get so weak after lifting what seems like half a ton... then you look down and it was 10 lb. dumbbell. Embarrassing, let me tell you! On top of the scheduled stuff, the Green kids and Jon and I play just about every sport imaginable round the clock... basketball, football, soccer, volleyball, etc... So I get pretty sore sometimes. :) But I do it to stay fit.
In much the same way, getting off the spiritual couch and getting those muscles moving is tough, but REWARDING! It can enable you to take some pressure and heat that otherwise could easily knock you out of the race for God. It's effective! It give that boost when rusty parts would have started falling off the car.
Becoming spiritual giant doesn't happen overnight, just like a bodybuilder doesn't get big muscles on day 1. Give it some time, though, and the results will be not only be amazing, but lifesaving as well! When your atheist friend starts dragging the name of Jesus through the mud, you'll be able to speak with wisdom and boldness for the Lord. Something a spiritual couch potato couldn't do. Jesus will be magnified, sinners saved and lives changed, all because the abilities of a surrendered, unselfish, strong christian were put to good use.
So get off that spiritual lazy-boy and get moving for God! :) You'll be so glad you did.