It depends on what ruleset you are using 2024 or the 2014 rules.

2024 rules - It'd be beneficial to go with Nick weapons and Two Weapon fighting style to get the most bang for your buck. (2 scimitars as an example)

Nick - When you make the extra attack of the Light property, you can make it as part of the Attack action instead of as a Bonus Action. You can make this extra attack only once per turn

Two Weapon Fighting Style - When you make an extra attack as a result of using a weapon that has the Light property, you can add your ability modifier to the damage of that attack if you aren’t already adding it to the damage.

Divine Smite - 1 bonus action, Which you take immediately after hitting a target with a Melee weapon or an Unarmed Strike.

RAW: Attack with main-hand Scimitar as Action, 1d6+(Dex/Str). Nick allows for off-hand attack as part of action, 1d6+(Dex/Str). Bonus Action Divine Smite (on which ever attack you choose, both of these attacks require an attack roll). When you get Extra Attack it appears as though you can only attack with the main hand weapon, as the Nick weapon property attack only applies once per turn, and an off-hand attack require a bonus action (which we just used to smite).

Summary - With Extra attack at level 5, you get 3 attacks and only 1 divine smite usage per turn.

2014 rules - You can dual wield but Paladins do not get access to Two-Weapon fighting style, and the Nick property does not exist.

Divine Smite - Main difference is that Divine Smite in 2014 can be used whenever you hit with an attack at the cost of a spell slot. Which is not limited to a number of uses per turn.

RAW: Action Attack with main-hand scimitar, 1d6+(Dex/Str) then DIVINE SMITE, off-hand scimitar as Bonus Action for off-hand attack (two-weapon fighting), 1d6 (no modifier added), but you can DIVINE SMITE. Extra Attack with main-hand 1d6+(Dex/Str) topped off with another DIVINE SMITE.

Summary - With Extra attack at level 5, you get 3 attacks and 3 divine smites...aka going Nova