According to my extensive and laborious research (I Googled it) this ad appeared in the November 28, 1970 issue of TV Guide.

The small print reads:

The people who make music today read the Bible. It’s that kind of book. It can make things work for you. Read the Bible. Find out where all the music is coming from.

And if you don’t have a Bible of your own, we’ll send you one for only a dollar. Hard cover and everything. Just one should do it. The Bible lasts a long time.

Bibles are good for people on bummers, like “Pammie” in Sonny Bono’s preposterously epic “Pammie’s on a Bummer.” He doesn’t even start singing until after three minutes have passed! “Singing” might be too strong of a word, here.