4 strength is equivalent to 4.4% Enhanced Damage if you use a hammer. If you use a bow then go for 6 dexterity.
The best jewel at level 14 is probably:
+14 to maximum damage, 20% ED, 4 strength
If the character is using Dragon Talon or Smite, then the best jewel is:
20% ED, 4 strength, 6 dexterity, 40 AR or 15 mana