Strengthen - (Webster's 1828 Dictionary)
1. To make strong or stronger; to add strength to, either physical, legal or moral; as, to strengthen a limb; to strengthen an obligation.
2. To confirm; to establish; as, to strengthen authority.
3. To animate; to encourage; to fix in resolution.
Charge Joshua, and encourage him, and strengthen him. Deu 3.
4. To cause to increase in power or security.
Let noble warwick, Cobham and the rest, with powerful policy strengthen themselves.
STRENGTHEN, v.i. To grow strong or stronger.
The disease that shall destroy at length, grows with his growth, and strengthens with his strength.
Grows with his growth, and strengthens with his strength.