'Strengthens' in the Bible

A wise man is strong,And a man of knowledge strengthens his power;

But I (Gabriel) will tell you what is inscribed in the writing of truth. There is no one who stands firmly with me and strengthens himself against these [hostile spirit forces] except Michael, your prince [the guardian of your nation].

This is our [reason for] proud confidence: our conscience testifies that we have conducted ourselves in the world [in general], and especially toward you, with pure motives and godly sincerity, not in human wisdom, but in the grace of God [that is, His gracious lovingkindness that leads people to Christ and spiritual maturity].