Cant find the lyrics - Guard your heart

[1voice4god]

So I only know some of the lyrics and I'm sure I heard it on a CD that I got at church one time or it was a song we sang in choir but the parts I remember it goes
Guard your heart guard your heart may your mind be ever ready ever sober ever steady........(cant remember this part maybe something about pressing only toward the prize)
Guard your heart guard your heart like shepherd o'er his keeping.....

And I can't remember it but I know the tune