5-10 hand w/ a straddle, fairly deep

[Runner Runner]

Reasons to bet the turn:

How could he call your flop raise without at least having a 7 in his hand (depending on his sidecards he probably has 6-9 outs).

If a card above 7 falls on the river and he bets, do you still plan on raising?

You said he pays off lightly.

*I could understand your reasoning for doing this more if u had A7 on a 77A board.