Let your conversation (i.e. manner of life, or disposition) be without covetousness; be content with such things as ye have: for he ( αὔτος, emphatic) hath said, I will never (i.e. in no wise) leave thee, neither will I ever forsake thee.
The reference seems to be to Deuteronomy 31:6, κύριος ὁ θεός σου .. οὔτε μή σε ἀνῇ οὔτε μή σε ἐγκαταλίπῃ, the same assurance being repeated in Deuteronomy 31:8. But similar promises occur elsewhere in the Old Testament (see Genesis 28:15; Joshua 1:5; 1 Chronicles 28:20; Isaiah 41:17; "Est igitur instar adagii divini," Bengel).