1 Timothy 6:12 Fight the good fight of faith, lay hold on eternal life.

The spiritual nature of things is key, Paul is admonishing Timothy to turn away from the temporal such as fixing your eyes on money and youthful lusts, but go on to the eternal. Everything you see today will pass away, the form of this world is passing away. Jesus is the eternal treasure, seen with the eyes of our heart. Friends do not waste your life laboring for food (temporal things of this world) that perishes, but for food (living Word of God: things of the Spirit) that endures to everlasting life (John 6:27).

Do not lay up for yourselves treasures on earth, where moth and rust destroy and where thieves break in and steal; but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal.

Matthew 6:19,20