With the Currencies in Destiny constantly changing were forced to farm for different types of materials to progress with our characters. Ever since Bungie added weapon reforging at the Tower Gunsmith we now can use Motes of Light to re-roll our weapons for more desirable perks. However, because it can take a seemingly unlimited amount of rolls to get that “God Roll” on your weapon we now need Motes of Light more then ever.
Here are a few ways I’ve found to quickly farm Motes of Light.
Trade in Coins with Xur at the Tower on the Weekends. For 2 Strange Coins you can get 1 Mote of Light. As long as your doing the Weekly Strike on hard you should have at least 27 coins to trade in.
Trade in Ascendant Materials with the Speaker at the Tower. For 2 Ascendant Shards you can get 1 Mote of Light. If you do the Vault of Glass Raid and open all the chests and dismantle the armor and weapons you get, you should end up with quite a bit to trade in for Motes. Also you can trade 2 Ascendant Energy for 1 Ascendant Shard with the speaker to put towards Motes.
Do Strikes and break down any Engrams you can get. When you break down Blue Engrams at the Cryptarch you have a change of getting Motes of Light, Strange Coins, Armor, or Weapons.
Hope this helps you out!