You will be forgiven if you don't know what that is. Before a practice or performance a guitarist will often spend minutes hunched over such a box, focussed intently on its flashing lights and arm moving on the screen. The box itself makes no music, but if the guitarist wants her music to sound 'right', even more if she wants to play along with other musicians, the guitar must first be brought into accordance with the box. It is a guitar tuner.
For the same reason, Christians need to spend time as often as possible in prayer and reading the Bible. These precious times allow us to tune our thoughts, desires, and feelings into harmony with God's. When our lives feel dischordant and out of tune our greatest need is to reorientate our inner world according to the music we find in scripture and the great composer we meet in prayer. Then we will know what it is to live in harmony, not with the world around us but the transcendent reality of God. The same God who will one day bring all things into his loving and glorious harmony.