Psalm 86:16

O turn unto me, and have mercy upon me
For it seems the Lord had turned away from him, and had hid his face, and withheld the manifestation of his grace and mercy from him, and had not yielded him the help and assistance he expected; and therefore entreats that he would turn again to him, and show him his face and favour, and be merciful to him:

give thy strength unto thy servant;
spiritual strength, strength in his soul, to exercise grace, perform duty, bear the cross, and stand up against all enemies, and hold out to the end: this is God's gift; and the psalmist pleads his relation to him as his servant, not merely by creation, but by grace; this is interpreted by the Jews of the King Messiah ^F21:

and save the son of thine handmaid;
out of the hands of those that were risen up against him; see ( Psalms 119:94 ) . Some think this has a special reference to Christ, who was made of a woman, called an handmaid, ( Luke 1:48 ) , born of a virgin, the son of Mary: Arama says David uses the word "handmaid", because he sprung from Ruth the Moabitess.