It is illegal.
OTHER PROHIBITED ACTS
Article 5
(a) (b)
(c) (d)
No offensive player may:
lift a runner to his feet or pull him in any direction at any time; or;
use interlocking interference, by grasping a teammate or by using his hands or arms to encircle the body of a teammate; or
trip an opponent; or
push or throw his body against a teammate to aid him in an attempt to obstruct an opponent or to recover a loose ball.
Penalty: For assisting the runner, interlocking interference, tripping, illegal use of hands, arms, or body by the offense: Loss of 10 yards.
https://www.nfl.com/static/content/public/image/rulebook/pdfs/15_Rule12_Player_Conduct.pdf