Psalms 152 to 155 are additional Psalms found in the Syriac Peshitta and, for two of them, in the Dead Sea scrolls. Together with Psalm 151 they are also called the 'Five Apocryphal Psalms of David'.
Psalm 152
"Spoken by David when he was contending with the lion and the wolf which took a sheep from his flock."[1]. This text survived only in Syriac and the original language may be Hebrew. The tone is non-rabbinical and it was probably composed in Palestine during the Hellenistic period.
Psalm 153
"Spoken by David when returning thanks to God, who had delivered him from the lion and the wolf and he had slain both of them."[1]. This text survived only in Syriac. Date and provenance are like psalm 152.
Psalm 154
This Psalm survived in the Syriac Peshitta and also was found in Hebrew, in the Dead Sea scroll 11QPs(a)154 (said also 11Q5), a first-century CE manuscript. The main theme is the request to "join yourselves to the good and to the perfect, to glorify the Most High". There is also a hint to common meals, typical of Essenes: "And in their eating shall be satisfying in truth, and in their drinking, when they share together"'.
Psalm 155
This psalm extant in Syriac and also was found in the Dead Sea scroll 11QPs(a)155 (said also 11Q5), a first-century CE Hebrew manuscript. The theme of this psalm is similar to Psalm 22, and due to the lack of peculiarities it is impossible to suggest date and origin.
Notes
1. ^ a b title from W. Wright Some Apocryphal Psalms in Syriac, Proceedings of the Society of Biblical archaeology 9 [1887] 257–266,
http://en.wikipedia.org/wiki/Psalms_152%E2%80%93155