Paul instructed to "put on the new self who is being renewed" (Col 3:10). Also, "put on a [new] heart" (:12) and "put on love" (:14). To put something on applies figuratively to clothes which are basically a covering. The new self entails "a true knowledge according to the image of the One who created him" (:11) in terms of "the likeness of God [which] has been created in the righteousness and holiness of the truth" (Eph 4:24). The new self walks "in a manner worthy of the calling with which you have been called" (:1) with the goal of preserving "the unity of the Spirit" (:3). This is accomplished "with all humility and gentleness, with patience, showing tolerance for one another in love" (:2). Also, "put on a heart of compassion, kindness, humility, gentleness and patience; bearing with one another, and forgiving each other" (Col 3:12-13). Paul instructs "being diligent to preserve the unity of the Spirit in the bond of peace" (Eph 4:3). In addition, "put on love, which is the perfect bond of unity" (Col 3:14). The bond of unity and peace is in and of the Spirit which is why you must put on the grace (divine enablement via unmerited favor) to make it possible.
Love is the "perfect" (Col 3:14) way to "preserve" (Eph 4:3) unity. It comes from "a heart of compassion [and] kindness" (Col 3:12). You have compassion when you sympathize with another person's misfortunes and are disposed to help and be merciful and gracious. It is in the context of "when you encounter various trials" (Ja 1:2) which requires "patience" (Eph 4:2, Col 3:12). Then this "testing of your faith produces endurance" (Ja 1:3) which has "its perfect result" (:4). Endurance is based upon having patience which is the ability to persevere through trouble without complaining or losing control. Patience is centered on an internal attitude that is a spiritual matter. You may have to submit to circumstances for a while and tolerate problems while calmly waiting for the situation to resolve itself. It is important to show "tolerance for one another in love" (Eph 4:2). Others have beliefs and ways of doing things. To put up with them without getting provoked is forebearance. You can recognize and respect these differences without having to compromise your own standards. To achieve unity you will also need humility (Eph 4:2, Col 3:12). Spiritually it is dependant on acknowledging God's grace as opposed to being prideful and self-assertive. Human shortcomings must be confronted which hopefully would lead a person to being more modest and unassuming and less pretentious and obtrusive. Gentleness (Eph 4:2, Col 3:12) and kindness (:12) are also required. To be gentle is to be mild-mannered such that you don't easily lose your temper. It is to be soft-hearted and not given to offensive communication. Kindness is being in the habit of being friendly, generous and affectionate. "Whoever has a complaint against anyone, just as the Lord forgave you, so also should you" (:13).