Consider two Christians who both do the exact same things:
A B
Reads his Bible and prays everyday Reads his Bible and prays everyday
Goes to church 3 times a week Goes to church 3 times a week
Doesn’t drink alcohol Doesn’t drink alcohol
Doesn’t do x, y, and z Doesn’t do x, y, and z
On and on …. On and on ….

Which one is the legalist? Since Scripture doesn’t use the term legalist, but it is commonly used among professing Christians, we ought to clarify our definition of legalism used here in context. Perhaps it would be fair to say the legalist is the one who makes those choices to look good to others and/or earn favor with God. The other man, who does the exact same things as the legalist, makes his choices out of love for his Lord Jesus and the desire to please Him. The legalist serves himself and the other his God. “Every way of a man is right in his own eyes: but the LORD pondereth the hearts” (Proverbs 21:2). 

The difference between the two is not seen in actions but in heart motives. The Lord knows which it is because He looks at the heart of man. The legalist is self-centered while the other, who seeks to please God, is God-centered. The legalist does good things or restricts himself from the world to earn praise from God or others. Obviously, no one other than the Lord can know the motives of a man’s heart. “Even so ye also outwardly appear righteous unto men, but within ye are full of hypocrisy and iniquity” (Matthew 23:28). 

“And he that sent me is with me: the Father hath not left me alone; for I do always those things that please him” (John 8:29). Jesus said, “…follow Me” (Matthew 16:24). 

Brothers, may we follow Him to please Him, because we love Him Who died for us.