Halladay is 8-3 (10-3 on the ML) with an ERA of 2.56 this season and the Phillies have won 6 of his 7 home starts. This tells us there's a good chance the Phillies will win. The preceding paragraph tells us there's a good chance the Cubs will lose by at least 2 runs when they fall.
Halladay is 25-5 on the money line in his last 30 starts when priced as a favorite of -175 to -250. His teams are winning these games by an average of 2.7 runs. Take Philly on the run line.