Psalms 138:3

In the day when I cried thou answeredst me
When in distress through Saul's persecution, he cried to the Lord, and he immediately answered him, and delivered him out of his troubles; and such immediate answers of prayer are to be remembered with thankfulness: see ( Psalms 18:6 ) ( Isaiah 65:24 ) ;

[and] strengthenedst me [with] strength in my soul;
put him good heart and spirit, when before ready to faint; strengthened his heart and grace in it, particularly faith, and drew it forth into lively act and exercise so that he sunk not under the weight of affliction and trouble, but was filled with courage to withstand his enemies, and with strength to do the will and work of God; this is to be understood of inward spiritual strength; see ( Ephesians 3:16 ) .