lion's eye diamond and retrace.

[TheRogue]

Say i have a land card in hand to pay the retrace cost of flame jab but only mana avalible is from lion's eye diamond. does lion's eye diamonds discard your hand activation cost make it impossible to play retrace costs with lion's eye diamond mana?

[Yare]

It is impossible.

Lion's Eye Diamond can only generate mana for you in between casting spells, activating abilities, etc.; you can't do it while you're casting a spell. So, if you try to play the card with retrace without popping LED, you won't have any mana when it comes time to pay up. Alternatively, if you pop LED then try to play the retrace spell, you'll have already discarded, so you won't be able to pay the "discard a land card" part of the cost. You can't cast the retrace spell in this scenario.

[SiegeX]

Lion's Eye Diamond can only generate mana for you in between casting spells, activating abilities, etc.; you can't do it while you're casting a spell

Technically you *can* generate mana while you are casting a spell, however, you cannot pay costs before you have activated all mana abilities.  Consider rules 601.2a-g which describes the order of what must be done to play a spell. In particular, look at step a, f and g below:

601.2a. The player announces that he or she is casting the spell. That card (or that copy of a card) moves from the zone it's in to the stack. It becomes the topmost object on the stack. It has all the characteristics of the card (or the copy of a card) associated with it, and that player becomes its controller. The spell remains on the stack until it's countered, it resolves, or an effect moves it elsewhere.

601.2f. If the total cost includes a mana payment, the player then has a chance to activate mana abilities (see rule 605, "Mana Abilities").Mana abilities must be activated before costs are paid.

601.2g. The player pays the total cost in any order. Partial payments are not allowed. Unpayable costs can't be paid.

Once you have announced the spell ala 601.2a, you are in the midst of casting that spell. It's not until step 'f' that you actually need to generate the mana.  Pay particular attention to the part of rule 601.2f that I highlighted in bold.  Since Lion's Eye Diamond is a mana ability, you must activate it first before you  can move on to step 'g' and pay the total cost of a retraced Flame Jab.  As mentioned, since part of Lion's Eye Diamond's activation cost is to discard your hand, you will not have a hand left when it comes time to satisfy 601.2g.

Hopefully I didn't come off as an ass in this post.  Many people are so accustomed to tapping mana before they announce the spell that they don't know they are actually allowed to do that much later during the process of casting the spell.

[LotusHead]

Lion's Eye Diamond can only generate mana for you in between casting spells, activating abilities, etc.; you can't do it while you're casting a spell

Technically you *can* generate mana while you are casting a spell, however, you cannot pay costs before you have activated all mana abilities.  Consider rules 601.2a-g which describes the order of what must be done to play a spell. In particular, look at step a, f and g below:

601.2a. The player announces that he or she is casting the spell. That card (or that copy of a card) moves from the zone it's in to the stack. It becomes the topmost object on the stack. It has all the characteristics of the card (or the copy of a card) associated with it, and that player becomes its controller. The spell remains on the stack until it's countered, it resolves, or an effect moves it elsewhere.

601.2f. If the total cost includes a mana payment, the player then has a chance to activate mana abilities (see rule 605, "Mana Abilities").Mana abilities must be activated before costs are paid.

601.2g. The player pays the total cost in any order. Partial payments are not allowed. Unpayable costs can't be paid.

Once you have announced the spell ala 601.2a, you are in the midst of casting that spell. It's not until step 'f' that you actually need to generate the mana.  Pay particular attention to the part of rule 601.2f that I highlighted in bold.  Since Lion's Eye Diamond is a mana ability, you must activate it first before you  can move on to step 'g' and pay the total cost of a retraced Flame Jab.  As mentioned, since part of Lion's Eye Diamond's activation cost is to discard your hand, you will not have a hand left when it comes time to satisfy 601.2g.

Hopefully I didn't come off as an ass in this post.  Many people are so accustomed to tapping mana before they announce the spell that they don't know they are actually allowed to do that much later during the process of casting the spell.

You can only use/sac LED when you can play an instant, ie NOT in the middle of casting another spell.

[SiegeX]

Ahh, my apologies. That's what I get for not reading the Oracle text. I see they added errata which adds the text Activate this ability only any time you could cast an instant. I'm sure that was put in place specifically so you could *not* activate it during 601.2f.  This makes sense because otherwise you could announce a draw7 like Timetwister then pay for it with LED much like it was a lotus.

However, sans the three cards that have this text (LED, Charmed Pendant and Rhystic Cave), you can use a mana ability in the middle of casting the spell.  Doing it this way can have some functional differences over you activating a mana ability prior to casting the spell.  A simple example would be sac'ing a lotus to cast some spell with Disciple of the Vault in play.  If you sac the lotus during 601.2f, the disciple trigger will go on the stack on top of, and thus resolve before, the spell you just cast.

[LotusHead]

That stuff is also relevent to Affinity players announcing say, Myr Enforcer with a Chromatic Sphere in play.  The sphere would count for affinity (during the calculate costs part), then help pay for it (during the pay mana/costs part).