I exhort therefore, first of all, that petitions, prayers, intercessions, and givings of thanks, be made for all men:
The supplications are petitions addressed to God; prayers include petitions but also thanksgivings, adorations, etc.; intercessions are usually thought of as pleas upon behalf of others; and the thanksgivings are expressions of gratitude and appreciation for blessings God has already bestowed, no prayer, in any sense, being complete without thanksgivings.