Forwards and futures are the basis of derivates. First of all when you buy a security like a share you buy

1. capital => you could sell to recieve capital back
2. voting rights => vote at the general assembly
3. dividend => depend on the companies dividend policy
4. price risks => depend on price fluctuations

Though when you buy a forward or a future => you buy only the price risk and trade it separately in the market. This is called either future, forward or a swap (delta one derivatives). It isolates the price risks of the share and is a contract providing pure exposure to the price risk of the underlying (e.g. share). Thus delta one derivates (dod) are used to manage the risk. This activity is called HEDGING the risk.

The future contract includes a price, quanity and quality you agree TODAY and of course the date at which the payment will be made in the future. This is the expiry or expiration date.
Forwards trade over the counter and Future trade on an exchange. Thus forwards are more like to be held until expiry and futures are more like to be closed out prior to expiry.

So now the question is how does the bank price and hedge a forward? For this you have to consider the price of the share today, the dividends of the company and date the bank fixes the expiry. Further the bank has to fix the price for settlement in XYZ forward time. Now the challenge: it does not know what the price will be and needs a plan to manage the risk. The bank borrows money eg. at 1% interest rate and buys the share today cash. It receives dividens until expiry thus calculates the net costs or all in costs, which will not change at any price of the share in the future.

The bank sells the forward to the client at this all-in or net carry cost plus a profit margin, with no risk and making good business. 

What is the arbitrage pricing ? There are two universal formula to calculate the forward price (arbitage-free):

1) F (forward price) = Spot + Basis (difference between forward and spot price)

2) F (forward price) = Spot + Cost (of holding the asset) – Benefit (of holding the asset)

If the forward price is set like that (considering the cost of hedging the position) no arbitrage is possible.

But if the forward trades with a higher value at actual market there is an arbitrage opportunity for the bank.

For example: The bank buys a share for 100,- CHF today and sells the forward at the expiry for 99. It borrows 100 to buy the share and returns 101 (at 1% interest) at the expiry, with receiving 3 CHF in time dividends the bank made automatically + 1 CHF profit without any risk. Magic.  Certain gain without market risk. However dividend risk still applies. 

Arbitrage pricing is a tool to valuate a derivate which assumes that the underlying (share) is a homogenous good, there are no barriers in buying/ selling / borrowing, interest rate is the same for borrowing / lending and the benefits are the same for all owner. This is the case of the S&P index but not live cattles for example. However futures on live cattles exist, which price is driven by supply and demand forces in time (barbecue time). This shows that the asset can not be carried.

A future curve shows the future expiry (time) and price of the underlying. The curve depends on interest rates and dividends (net carry costs).