The Songs of Jesus refer to the Psalms, which are the only songs given by inspiration to the Church for public worship. Moreover, as Michael LeFebvre puts it in his book 'Singing the Songs of Jesus', "...it is in the Biblical Psalms alone that Jesus himself, our priestly king, leads our sung proclamations in the presence of the Father... [so that when] you sing the Psalms, you are actually singing the songs of Jesus, with Jesus as your songleader."
This is a no-frills app for those who'd like to have convenient access to the 1650 Scottish Psalter (Metrical Psalms) on their mobile devices. The text of the Psalter is from 'Scottish Psalter and Paraphrases' (http://www.ccel.org/ccel/anonymous/scotpsalter), edited minimally to correct typographical errors.
"Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord." Colossians 3:16.