Foundation of Stone

(Spell Compendium, page 99, DnD 3.5)

Transmutation[Earth]

Level: ; Cleric 1; Druid 1
Components: V, S
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One creature/level, no two of which are more than 30 ft. apart
Duration: 1 round/level
Saving Throw: None
Spell Resistance: No

Calling upon the strength of the earth, you lend some of the stability of stone to your allies.

As long as they do not move and remain standing on solid ground, the subject creatures gain a +2 bonus to Armor Class and a +4 bonus on Strength checks made to resist being bull rushed or tripped.

If this spell is cast in mountainous terrain, the bonus on Strength checks granted by this spell increases to +6.