The question of the title is a focus on the difference between complement and compliment.  Even though the difference between the spellings of the two words is nothing more than a single vowel, there is a significant difference in their meaning:

• A complement completes, enhances, or perfects.
• A compliment is the expression of praise, admiration, or in some cases it is used in regard to a free gift.

Both words offer an appropriate expression of your relationship with Jesus:

• Because salvation is a free gift to you from God, Jesus is a compliment: “For God so loved the world that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life (John 3:16).”
• Salvation is also the complement through which He completes, enhances, and perfects you: “For in Him all the fullness of Deity dwells in bodily form, and in Him you have been made complete, and He is the head over all rule and authority (Colossians 2:9-10).”

As you start your week, I encourage you do so with a spirit of thanksgiving for the manner in which God has complimented you and continues to complement you.