What is the difference between petitioning and sponsoring in immigration vernacular?

If anyone chooses to sponsor their relative's Immigration by filing a relative petition (I-130), then they must also agree to be his or her financial sponsor and file the financial affidavit of support. Thus, sponsoring refers more to supporting an immigrant financially while petitioning to filing the proper applications/petitions (i.e., I-130 and, if an immigrant lives in the US, I-485). However, very frequently these terms are used interchangeably.