The phrase spiritual songs in the verse above means songs of the spirit. The apostle paul made the same reference in 1corinthians 14vs14-15 when he talked about singing in tongue's singing in the spirit. Singing with the spirit in other tongue these songs come out of your spirit not from your understanding it is similar to the way you yield your tongue to the holyspirit to pray in tongue only that this time you are singing in other tongue and worshipping the lord. John 4 vs 24 worshipping in the spirit climax you may sing and worship the lord in your understanding and that's okay but ascend higher sing songs of the spirit from your spirit worship and relate from your spirit it is a deeper fellowship.