Infantry Shield attached to a creature you control with power 5 or greater that does not have summoning sickness and cannot be blocked and killed by an opponent).
Steps
Declare the creature that has
Infantry Shield attached as an attacker, triggering its ability, creating a number of 1/1 Warrior creature tokens that are tapped and attacking equal to the creature's power.
Holding priority, activate
Phyrexian Altar five times by sacrificing five Warriors, adding ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Activate
Najeela by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat.
Notes
If Hellkite Charger has power 7 or greater, you can attach
Infantry Shield to it. Just ensure to resolve the token creation ability first.