"And David was greatly distressed; for the people spake of stoning him, because the soul of all the people was grieved, every man for his sons and for his daughters: but David encouraged himself in the LORD his God." (1 Samuel 30: 6)
When I read this passage, I often wondered how David strengthened himself.
We have no strength in ourselves, anyway, since apart from Christ Jesus, we can do nothing (John 15: 5)
The first mention of "strengthen" (Chazak in Hebrews) occurs in Genesis 19:
"And while he lingered, the men laid hold upon his hand, and upon the hand of his wife, and upon the hand of his two daughters; the LORD being merciful unto him: and they brought him forth, and set him without the city." (Genesis 19: 16)
The two angels had warned Lot and his family to flee from Sodom and Gomorrah. Lot tried to persuade his sons-in-law to flee with him, but they did not believe him. Even Lot hesitated a little, not knowing what to do.
The two angels, seized, or rather strengthened, Lot's hand and delivered him and his wife and daughters out of the house, then out of the city.
In the same way, let us not look to our own strength, since we will hesitate and lose. Instead, let us rest and receive our strength from God's hand, for in Him we find our strength:
"My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand." (John 10: 29)
Our strength is His strength!
And of course:
"I can do all things through Christ which strengtheneth me." (Philippians 4: 13)
A literal translation would read:
"In all things I am strong through the one who is strengthening me".
Jesus is ever more working in us both to will and to do for His good pleasure (Philippians 2: 12-13)
If David was strengthened while under an old Covenant based on the blood of bulls and goats, how much stronger are we, who are ever cleansed, ever blessed by the precious, incorruptible, eternal blood of Jesus?
Our strength is Jesus who holds us, and we can know and believe that He holds us because He died for us and lives for us, justifying us at the right hand of God the Father.