Throughout history, various motives have moved men to sing unto the Lord. Some men sang as a testimony of some specific thing God had done for them (Exodus 15:1; Psalm 126:1-2). Others sang in order to teach truths set forth in the word of God (Colossians 3:16; Psalm 101:1). Some even sang songs that would testify against them in times of disobedience (Deuteronomy 31:19). Though some things have changed throughout history, God’s people still should sing songs of personal testimony like My Jesus, I Love Thee; songs that teach like Holy and Reverend Is the Name; and songs that witness against disobedience like He Was Not Willing.
Reading commentaries offers varying opinions concerning the definition of purity. However, the Bible offers some exacting details which give the right definition. Today's passage speaks of the “pure blood of the grape.” In other words, nothing was added to the juice—it was pure. There are several other substances in scripture identified as pure: gold (Exodus 25:39), olive oil (Exodus 27:20), myrrh (Exodus 30:23), incense (Exodus 37:29), and language (Zephaniah 3:9). Each instance emphasizes that nothing exists to corrupt the nature of the original. These substances are not combined with other materials to dilute or defile them. In essence, purity demands the absence of any substance that corrupts, defiles, or taints in any way.