Declare Mobile Garrison and Najeela, if able, as attackers.
Mobile Garrison triggers, as well as Najeela if it was declared an attacker.
Resolve the Mobile Garrison trigger, untapping Bloom Tender.
Resolve the Najeela trigger, if applicable, creating a 1/1 Warrior creature token that is tapped and attacking.
Holding priority, activate Bloom Tender by tapping it, adding .
Activate Najeela by paying , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat each combat phase.
This ingenious loop turns Najeela, the Blade-Blossom into a relentless one-person army by using Mobile Garrison's attack trigger to untap Bloom Tender. Because Bloom Tender looks at the colors of all your permanents—including a five-color commander like Najeela—it single-handedly produces the exact five-mana bounty of {W}{U}{B}{R}{G} needed to fuel Najeela's activated ability. Once Najeela grants your attackers an additional combat phase, Mobile Garrison and Bloom Tender are ready to reset all over again, generating infinite combat steps, tokens, and lifegain.