The intention behind the seditious activity is to bring hatred or contempt or excite disaffection against the Government of India while abetting of waging war against the Government of India is the instigation of necessarily waging of war. Sedition takes into account overt act like delivering seditious speech or organizing rallies with a motive or exciting disaffection by citing seditious slogans. On the other hand, abetting to wage war negates all the acts of mere instigation but actual committing of war.
The general Law of abetment is laid down from Section 107 to 120 of IPC, which states that it is not necessary that the act abetted should be completed in order to constitute the offence of abetment. The same applies to waging war against the Government of India as it applies to any other offences under IPC. The only difference is that under the general Law, there is a separate punishment for abetment which has been completed and which has been failed, but under Section 121, no such distinction has been made. Abetment of waging war against the Government of India and actual waging of war are dealt on the same footing and has to be nipped in the bud with a strong hand.